Context Use to Improve the Speech Understanding Processing
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Improving Listening Comprehension andSpoken English SkillsIn the globalized world, proficiency in English has become a prerequisite for effective communication and career success. Among the four basic language skills - reading, writing, speaking, and listening - listening comprehension and spoken English skills are particularly crucial for fluent communication. Improving these skills requires a conscious effort and dedication to practice. Here are some strategies that can help you enhance your listening comprehension and spoken English abilities.**1. Regular Exposure to English**The key to improving listening comprehension is regular exposure to English. This can be music achieved by watching English movies, listening to English, podcasts, or news broadcasts, and reading English materials. This exposure helps you familiarize yourself with the language's pronunciation, vocabulary, and grammar, thereby improving your understanding.**2. Active Listening**Passive listening is not sufficient to improve your comprehension. You need to actively engage with the content you are listening to. This involves actively thinking about what you hear, asking questions, and attempting to summarize the information. Active listening helps youretain and process information better.**3. Practice Speaking**Speaking is the other crucial skill that complements listening comprehension. The best way to improve your spoken English is to practice speaking regularly. Join English clubs, participate in debates, or simply speak to yourself in English. This helps you familiarize yourself with the language's pronunciation, intonation, and flow.**4. Record Yourself and Analyze**Recording yourself while speaking English and analyzing your performance can help identify areas of improvement. Listen to your recordings and note down areas where you struggle with pronunciation, vocabulary, or grammar. Then, work on these areas by practicing them repeatedly.**5. Seek Feedback**Feedback is crucial for improving any skill, and English speaking is no exception. Seek feedback from native speakers or teachers who can point out your mistakes and suggest improvements. Accepting and implementing feedback can help you improve your speaking skills significantly.**6. Use Technology**There are numerous technological tools available that can help improve your listening comprehension and spoken English skills. Language learning apps, online courses, and virtual reality simulations are just a few examples. These tools provide convenient and engaging ways to practice your skills.In conclusion, improving listening comprehension and spoken English skills requires a conscious effort and dedication to practice. By regularly exposing yourself to English, actively listening, practicing speaking, recording and analyzing your performance, seeking feedback, and utilizing technology, you can significantly enhance your English proficiency. Remember, consistency and persistence are key to achieving success in language learning.**提高英语听力理解和口语能力**在全球化的世界里,英语熟练度已成为有效沟通和职业成功的先决条件。
2023年全国卷甲CD篇二次开发一、阅读下列短文,从每题所给的A、B、C和D四个选项中, 选出最佳选项。
CI was about 13 when an uncle gave me a copy of Jostein Gaarder’s Sophie’s World. It was full of ideas that were new to me, so I spent the summer with my head in and out of that book. It spoke to me and brought me into a world of philosophy (哲学).That love for philosophy lasted until I got to college. Nothing kills the love for philosophy faster than people who think they understand Foucault, Baudrillard, or Confucius better than you — and then try to explain them.Eric Weiner’s The Socrates Express: In Search of Life Lessons from Dead Philosophers reawakened my love for philosophy. It is not an explanation, but an invitation to think and experience philosophy.Weiner starts each chapter with a scene on a train ride between cities and then frames each philosopher’s work in the context (背景) of one thing they can help us do better. The end result is a read in which we learn to wonder like Socrates, see like Thoreau, listen like Schopenhauer, and have no regrets like Nietzsche. This, more than a book about undestanding philosophy, is a book abour learning to use philosophy to improve a life.He makes philosophical thought an appealing exercise that improves the quality of our experiences, and he does so with plenty of humor. Weiner enters into conversation with some of the most important philosophers in history, and he bees part of that crowd in the process by decoding (解读) their messages and adding his own interpretation.The Socrates Express is a fun, sharp book that draws readers in with its apparent simplicity and gradually pulls them in deeper thoughts on desire, loneliness, and aging. The invitation is clear: Weiner wants you to pick up a coffee or tea and sit down with this book. I encourage you to take his offer. It’s worth your time, even if time is something we don’t have a lot of.()1. Who opened the door to philosophy for the author?A. Foucault.B. Eric Weiner.C. Jostein Gaarder.D. A college teacher.()2. Why does the author list great philosophers in paragraph 4?A. To pare Weiner with them.B. To give examples of great works.C. To praise their writing skills.D. To help readers understand Weiner’s book.()3. What does the author like about The Socrates Express?A. Its views on history are wellpresented.B. Its ideas can be applied to daily life.C. It includes ments from readers.D. It leaves an open ending.()4. What does the author think of Weiner’s book?A. Objective and plain.B. Daring and ambitious.C. Serious and hard to follow.D. Humorous and straightforward.二、词汇过关Para1&Para2&Para3① a copy of ________________②philosophy n.____________ philosopher③nothing ...faster than ...___________;_______________④reawaken v.______________ awake⑤________________⑥___________ n.邀请__________ v.邀请_________________邀请某人做某事Para4&Para5⑦chapter n._________⑧scene n._________⑨frame v.______; ______ ⑩appealing11improve the quality of our experiences _____________________________12enter into conversation ________________________13crowd n.__________ __________adj. 拥挤的14_________________ 在这个过程中15decode their messages ________________16add his own interpretation_________________Para617____________ 一本犀利的书18______________ 吸引某人的注意19apparent20simplicity21with its apparent simplicity _______________22pull sb. in deeper thoughts _________________23_________ n.&v. 渴望24aging25loneliness26___________ n. 邀请________ v.邀请____________________邀请某人做某事Qs27pare A with B _________________28give examples _______________29praise their writing skills _____________________30views on31wellpresented ______________32be applied to _____________ 33men34objective adj._______ subjective adj. ___________35plain36daring adj.____________37ambitious38straightforward三、长难句分析:①Nothing kills the love for philosophy faster than people who think they understand Foucault, Baudrillard, or Confucius better than you — and then try to explain them.分析:Nothing ... faster than ...译为_________________,此句中含有who 引导的_______从句,修饰先行词_____________。
英语作文怎样提高发音能力Improving English pronunciation is a multifaceted task that requires consistent practice and dedication. Here are some effective strategies to enhance your pronunciation skills:1. Listen and Mimic:One of the most effective ways to improve pronunciation is by listening to native speakers and mimicking their speech patterns. 。
Watch English movies, TV shows, and listen to English podcasts or radio programs to expose yourself to various accents and intonations.2. Use Pronunciation Tools:Utilize online resources and apps specifically designed to help improve pronunciation, such aspronunciation guides, phonetic dictionaries, and speech recognition software.These tools can provide instant feedback on your pronunciation accuracy and help you identify areas for improvement.3. Practice Tongue Twisters:Tongue twisters are excellent exercises for improving articulation and clarity of speech.Practice saying tongue twisters slowly at first, focusing on each individual sound, and gradually increase your speed as you become more comfortable.4. Record Yourself:Record yourself speaking English and listen to the recording critically.Pay attention to areas where your pronunciation maybe unclear or incorrect, and make a conscious effort to correct those mistakes in future practice sessions.5. Work on Stress and Intonation:English is a stress-timed language, which means certain syllables in words are emphasized more than others.Practice identifying and placing stress on the correct syllables in words and sentences to improve your overall rhythm and intonation.6. Seek Feedback:Practice speaking English with native speakers or fluent speakers who can provide constructive feedback on your pronunciation.Don't be afraid to ask for help or clarification when you're unsure about how to pronounce a word or phrase correctly.7. Join Pronunciation Classes or Groups:Consider enrolling in pronunciation classes or joining language exchange groups where you can practice speaking English with others who are also looking to improve their pronunciation.Collaborating with peers can provide motivation and support as you work towards your pronunciation goals.8. Be Patient and Persistent:Improving pronunciation takes time and consistent effort, so be patient with yourself and celebrate your progress along the way.Set achievable goals and commit to regular practice sessions to maintain steady improvement over time.By incorporating these strategies into your English learning routine and staying committed to regular practice, you can significantly enhance your pronunciation skills andcommunicate more effectively in English. Remember, consistency and perseverance are key to success!。
英语如何利用学习语音工具提高发音准确性IntroductionBeing able to pronounce English words accurately is an essential aspect of language learning. A good pronunciation not only helps in effective communication but also boosts confidence. To achieve better pronunciation, learners can make use of various phonetic tools and techniques. This article explores different ways in which English learners can leverage these resources to enhance their pronunciation skills.1. Phonetics and PhonologyPhonetics is the study of sounds in human speech, while phonology focuses on the patterns and rules governing these sounds. A solid understanding of phonetics and phonology is crucial for improving pronunciation. Language learners should familiarize themselves with the different phonetic symbols and their corresponding sounds. Tools such as phonetic charts and phonetic dictionaries, available online or in books, can be immensely helpful in this context.2. Pronunciation Practice AppsTechnology has revolutionized language learning, and there are now numerous pronunciation practice apps available. These apps provide learners with interactive exercises, audio examples, and real-time feedback. Some popular options include ELSA Speak, Sounds: The Pronunciation App, and Speak English Fluently. Utilizing these apps regularly can help learners develop muscle memory and improve their pronunciation accuracy.3. Online Pronunciation CoursesThere are several online platforms offering comprehensive pronunciation courses. These courses are designed to address specific pronunciation difficulties faced by learners. They focus on individual sounds, stress patterns, intonation, and syllable divisions. Websites such as Udemy, Coursera, and FluentU offer a wide range of pronunciation courses suitable for learners of various proficiency levels.4. Interactive Online ToolsVarious interactive websites provide learners with tools for practicing specific aspects of pronunciation. For instance, Forvo is an online pronunciation dictionary that allows learners to hear native speakers pronounce words and phrases. Easy Pronunciation offers animated videos that demonstrate the correct mouth movements for producing specific sounds. Practicing with such tools can significantly enhance pronunciation accuracy.5. English Language Learning SoftwareLanguage learning software, such as Rosetta Stone and Duolingo, often includes pronunciation exercises and interactive lessons. These tools integrate listening, speaking, and pronunciation practice into one comprehensive package. Learners can use such software to improve their pronunciation while also gaining a deeper understanding of English grammar, vocabulary, and sentence structure.6. Speech Recognition TechnologySpeech recognition technology is becoming increasingly sophisticated and can now provide accurate feedback on pronunciation. Voice recognition apps like Google Assistant and Siri can recognize spoken words and assist learners in assessing their pronunciation accuracy. Engaging with such technology on a regular basis can help learners identify their weaknesses and work on improving them.ConclusionImproving English pronunciation requires consistent practice and exposure to authentic language resources. The use of phonetic tools, pronunciation practice apps, online courses, interactive online tools, language learning software, and speech recognition technology can significantly aid learners in their journey towards better pronunciation. By utilizing these resources, learners can develop a more accurate and confident speaking style, ultimately enhancing their overall English language skills.。
When crafting an English essay on a speech,its important to consider the structure, content,and the impact the speech had on you.Heres a guide on how to write an effective speech review essay:Title:Reflections on a Memorable SpeechIntroduction:Begin with a brief introduction of the speech,including the speakers name,the occasion, and the general topic.Set the context for your readers.Paragraph1:Setting the SceneMention the date,time,and location of the speech.Describe the atmosphere and the audiences mood before the speech began.Paragraph2:Overview of the Speech ContentSummarize the main points the speaker covered.Discuss the structure of the speech,such as the introduction,body,and conclusion.Paragraph3:Analysis of the Speakers DeliveryEvaluate the speakers tone,pace,and use of language.Comment on the speakers body language and eye contact with the audience.Paragraph4:Personal Reaction to the SpeechShare your initial reaction to the speech and how it made you feel.Discuss any specific moments or quotes that stood out to you.Paragraph5:Impact of the SpeechReflect on how the speech has influenced your thoughts or actions.Consider the broader implications of the speechs message.Paragraph6:Critique and PraiseOffer constructive criticism on areas where the speech could have been improved. Praise the aspects of the speech that were particularly effective.Conclusion:Summarize your overall impression of the speech.End with a thoughtprovoking statement or a question that encourages readers to reflect on the speechs significance.Example Paragraphs:Introduction:Last week,I had the privilege of attending a speech by renowned environmental activist Jane Smith at the city library.The topic was The Future of Our Planet,a subject that resonates deeply with me and many others in the audience.Paragraph1:Setting the Scene:The librarys main hall was filled to capacity,with an air of anticipation palpable among the attendees.The dimmed lights and the hushed whispers created a sense of reverence, as if we were about to witness something truly significant.Paragraph4:Personal Reaction to the Speech:As Jane Smith began to speak,her passion for the environment was immediately evident. Her words painted a vivid picture of the challenges we face and the urgent need for action.I found myself nodding in agreement,feeling a surge of determination to contribute to the cause.Conclusion:In conclusion,Jane Smiths speech was not just an informative session it was a call to arms.It left me with a renewed sense of responsibility towards our planet and a commitment to act.I believe that such speeches are crucial in mobilizing individuals to become agents of change.Remember to use your own voice and personal insights to make the essay engaging and reflective of your genuine experience.。
如何提升语音能力作文英文回答:To improve my speaking ability, there are several strategies that I can adopt. Firstly, I can practice speaking with native speakers or language exchange partners. By engaging in conversations with them, I can not only improve my pronunciation and fluency, but also learn more about the culture and idiomatic expressions. For example, I can join language exchange groups or find language partners online to have regular conversations.Secondly, I can listen to and imitate native speakers. This can be done by watching movies or TV shows in thetarget language, listening to podcasts or audiobooks, and even repeating after native speakers. By doing so, I can improve my intonation, rhythm, and overall speaking skills. For instance, I can choose a TV series in the target language and watch it with subtitles, then try to imitate the actors' pronunciation and intonation.Thirdly, I can engage in real-life situations where I need to use the target language. For example, I can participate in language immersion programs or travel to a country where the language is spoken. By immersing myselfin the language environment, I can practice speaking in various contexts and improve my communication skills. Additionally, I can make an effort to use the target language in my daily life, such as ordering food in a restaurant or asking for directions.In conclusion, to enhance my speaking ability, I can practice speaking with native speakers, listen to and imitate native speakers, and engage in real-life situations where I need to use the target language. By consistently practicing and exposing myself to the language, I can gradually improve my speaking skills.中文回答:为了提升我的口语能力,我可以采取几种策略。
克服发音问题的更好方法英语作文Overcoming Pronunciation Problems: Better MethodsIntroductionPronunciation plays a crucial role in language learning as it directly affects communication. However, for many English language learners, overcoming pronunciation problems can be quite challenging. In this article, we will explore some effective methods to help learners improve their pronunciation skills and communicate more confidently in English.Understanding the Basics of PronunciationBefore we delve into specific techniques, it is important to understand the basics of pronunciation. English pronunciation is unique and can be quite different from other languages. Sounds in English can be tricky, especially for non-native speakers. To improve pronunciation, learners need to be aware of vowel sounds, consonant sounds, stress patterns, intonation, and rhythm.Effective Methods to Improve Pronunciation1. Practice PhoneticsPhonetics is the study of speech sounds and their production. By practicing phonetics, learners can familiarize themselves with the sounds of English and improve their pronunciation. They can use online resources, such as phonetic charts and audio recordings, to practice different sounds and learn how to produce them correctly.2. Listen and RepeatListening to native speakers is essential for improving pronunciation. Learners should listen to various accents and styles of English to get a better understanding of pronunciation variations. By listening and repeating after native speakers, learners can mimic the sounds and intonation patterns, helping them improve their pronunciation.3. Use TechnologyTechnology can be a useful tool for improving pronunciation. There are several language learning apps and software programs available that focus on pronunciation practice. These programs use speech recognition technology to provide feedback on pronunciation accuracy, helping learners identify and correct their mistakes.4. Engage in ConversationsPracticing speaking with others is crucial for improving pronunciation. Learners should engage in conversations with native speakers or fellow students to practice their pronunciation in a real-life context. Feedback from others can also help learners identify areas for improvement and work on them effectively.5. Record YourselfRecording yourself speaking English is a great way to monitor your pronunciation progress. By listening to recordings of your own speech, you can identify pronunciation errors, work on specific sounds, and track your improvement over time.Self-recording can also boost confidence and motivation in learners.6. Focus on Problematic SoundsCertain sounds in English can be particularly challenging for non-native speakers. Learners should identify these problematic sounds and focus on practicing them extensively. By dedicating extra time and effort to mastering difficult sounds, learners can overcome pronunciation obstacles more effectively.7. Practice RegularlyConsistent practice is key to improving pronunciation. Learners should incorporate pronunciation practice into theirdaily routine, dedicating a specific time each day to work on pronunciation skills. With regular practice, learners can gradually improve their pronunciation and build confidence in speaking English.ConclusionImproving pronunciation in English requires dedication, practice, and patience. By following these effective methods, learners can overcome pronunciation problems and communicate more effectively in English. Remember, the key to success is persistence and regular practice. Keep practicing, and you will see noticeable improvement in your pronunciation skills.。
怎样让语音变得更有感染力英语作文英文回答:To make your voice more persuasive and engaging, there are several techniques you can use. First and foremost, itis important to vary your pitch, tone, and volume. This helps to keep your audience engaged and interested in what you are saying. For example, if you are telling a story or conveying an emotion, you can raise your pitch slightly to add excitement or lower your tone to create a sense of seriousness.Another way to make your voice more infectious is touse pauses effectively. Pauses can help to emphasize important points or allow your audience to digest information. For instance, if you are giving a presentation, you can pause before delivering a key message to build anticipation and create a dramatic effect.Furthermore, using vocal inflections and gestures cangreatly enhance the impact of your voice. By emphasizing certain words or phrases with gestures, you can make your message more memorable and engaging. For instance, if you are talking about the importance of teamwork, you can use hand gestures to demonstrate cooperation and unity.Additionally, incorporating storytelling techniquesinto your speech can make your voice more compelling. People are naturally drawn to stories, so using anecdotes and personal experiences can help to captivate your audience. For example, if you are discussing the benefits of a healthy lifestyle, you can share a personal story about how adopting healthy habits transformed your life.In conclusion, to make your voice more infectious, it is important to vary your pitch, tone, and volume, use effective pauses, incorporate vocal inflections and gestures, and utilize storytelling techniques. By employing these strategies, you can captivate your audience and make your voice more persuasive and engaging.中文回答:要让你的语音更有感染力,有几种技巧可以使用。
如何提高你的听力理解和口语能力英语作文How to Improve Your Listening and Speaking SkillsImproving your listening and speaking skills in English is essential for effective communication and language proficiency. Whether you are a student, a professional, or someone learning English as a second language, developing these skills can open up a world of opportunities and enhance your overall language skills. Here are some tips on how to improve your listening and speaking skills:1. Practice Listening Comprehension:- Listen to various sources of English: To improve your listening skills, expose yourself to different forms of English, such as podcasts, radio programs, news broadcasts, and movies. This will help you get accustomed to different accents, speech patterns, and vocabulary.- Focus on understanding the main ideas: When listening to English content, try to focus on understanding the main ideas and key points. This will help you grasp the overall meaning of the conversation or the information being presented.- Take notes: Taking notes while listening can help you retain information and improve your comprehension. Write down keywords, phrases, or ideas that you hear to review them later and reinforce your understanding.2. Engage in Conversations:- Practice speaking regularly: The more you practice speaking in English, the more confident and fluent you will become. Try to engage in conversations with native speakers, language partners, or fellow learners to improve your speaking skills.- Join language exchange programs: Language exchange programs are a great way to practice speaking with native speakers and improve your conversational skills. These programs allow you to practice English in a relaxed and supportive environment.- Attend English-speaking events: Attend English-speaking events, social gatherings, or workshops to interact with native speakers and practice your speaking skills in real-life situations. This will help you build confidence and improve your fluency.3. Use Language Learning Apps and Tools:- Utilize language learning apps: There are many language learning apps available that can help you improve your listening and speaking skills. Apps like Duolingo, Rosetta Stone, andBabbel offer interactive exercises, conversation practice, and pronunciation drills.- Watch English videos with subtitles: Watching English videos with subtitles can help you improve your listening comprehension and pronunciation. Pay attention to how words are pronounced and try to mimic the speakers to improve your speaking skills.- Record yourself speaking: Record yourself speaking in English and listen to the recordings to identify areas for improvement. Practice speaking aloud, paying attention to your pronunciation, intonation, and fluency.4. Seek Feedback and Guidance:- Seek feedback from teachers or language partners: Ask for feedback from teachers, language partners, or native speakers to help you identify areas for improvement and focus on specific language skills.- Take language courses: Enroll in language courses or workshops that focus on listening and speaking skills. These courses provide structured practice, feedback, and guidance to help you improve your language proficiency.By following these tips and strategies, you can enhance your listening and speaking skills in English and become a more effective communicator. Remember that language learning is a journey, and consistent practice and dedication are key to improving your language skills. So keep practicing, stay motivated, and enjoy the process of learning and growing in English proficiency.。
Context Use to Improve the Speech Understanding ProcessingCaroline Bousquet-Vernhettes and Nadine VigourouxIRIT UMR CNRS 5505, Université Paul Sabatier, 118 Route de Narbonne, 31062 Toulouse, FranceAbstract: We developed an environment for speech understanding, based on a stochastic representation of conceptual entities. The conceptual segmentation can be performed with the Viterbi or A* algorithms. The aim of this paper is to propose a model of contextual knowledge to improve the speech understanding process. We will focus on the context provided by the system prompt and the dialogue history. We argue that the context could help the prediction of the conceptual segmentation of the utterance. So results obtained on understanding error rate and running time with and without contextual knowledge are discussed.INTRODUCTIONIn automatic inquiry systems one of the main research challenge is to make the understanding of user’s utterances robust. The speech understanding process consists in extracting the meaning of the utterance useful for the application. This meaning includes both referential information and illocutionary acts. This process must be able to understand a large public in spite of the difficulties: spoken natural language ambiguities, speech variability and choices of expression (indeed users express themselves spontaneously so they can hesitate, make errors or correct themselves) and errors introduced by the automatic speech recognition itself.We developed an environment for speech understanding, based on a stochastic representation of conceptual entities called CACAO (Compréhension Automatique par segments Conceptuels Assistée par Ordinateur i.e. computer-aided automatic understanding based on conceptual segments) (1). The conceptual segmentation is performed with the Viterbi or A* algorithms. The aim of this paper is to discuss how the contextual knowledge could be used as pragmatic predictions and how their modelling in CACAO could increase the understanding score rate and decrease the running time.Several approaches were developed by researchers: some used one language model for each dialogue state like in (2), (3) or (4). In (5) the authors proposed to search all the solutions and to remove those, which are in contradiction with the dialogue state. In (6) the authors modified the score of recognised solutions corresponding to the question asked by the system.In this paper, we will focus on contextual knowledge provided by the current system question and the dialogue history. Indeed, according to our study on more than 2860 speech turns, the user usually answers the question and gives additional information that is not present in the dialogue history. Our method is to increase the probabilities concerning conceptual segments that are most probable to appear in the utterance (for example conceptual segments answering the question asked).We will first describe the conceptual model. Then we will present how the context is modelled in this approach. Finally we will discuss preliminary understanding results obtained from a word graph input.A STOCHASTIC APPROACH BASED ON CONCEPTUAL SEGMENTWe have developed an understanding system based on stochastic representation of semantic and pragmatic knowledge using conceptual segments. The conceptual segment is a word sequence corresponding to the basic units of meaning. We distinguish two kinds of conceptual segments: referential conceptual segments representing the application domain and illocutionary conceptual segments referring to the speech act theory. In task-oriented domain (like train or airline reservation, cinema schedules and so on), the identification of conceptual segments is assumed to be finite. They are deduced from the manual analysis of the application. For example, the two following word sequences “about four o’clock” and “at half past two in the morning” are both represented by the same conceptual segment named hour. Consider, for train schedules application, the user’s sentence “I would like a train to Paris tomorrow at nine”; according our approach we obtain the following segmentation in four conceptual segments.The phrase “Imodelling although its surfaceform expresses a modality according the speech act theory. User’s utterances are labelled into a sequence ofconceptual segments as illustrated above. The language model of the application is represented by a graph of conceptual segments (modelled by a Hidden Markov Model (HMM) where states are the conceptual segments). Each conceptual segment is also represented by HMM where the states represent word classes. Word classes are introduced to facilitate the concept modelling: for instance, all the city names are grouped in the same word class called ‘towns’. We point out that to each conceptual segment corresponds its own lexicon, which is in fact a part of the global understanding lexicon. The CACAO modelling is inspired with the CHRONUS method (7).THE CACAO ENVIRONMENT AND THE CONTEXT MODELLING CACAO environment: It consists of four modules corresponding to the four states of the understanding process (see figure 1). The pre-processing module transforms the output of the speech recognition into the appropriate representation for the conceptual decoder. Words considered as unnecessary for the understanding process are removed (like hesitations). Only the N-best word sequences are retained. Each word sequence is then decomposed into a conceptual segment sequence, according to the model described above, with the conceptual decoder performed with the A* or the Viterbi algorithm. A* algorithm produces several solutions from a word sequence input whereas Viterbi delivers only one solution. Linguistic knowledge (lexicon and conceptual graphs) is used at this level. Several optimisation parameters allow the model to be adjusted for the understanding process (1). The decision module computes the confidence score of each solution using both the recognition (R) and understanding (U) confidence score and then identifies the best solution. The solution confidence score (S) is computed with the formula S = αR + (1-α) U where the αvalue was been defined experimentally. Finally, the solution retained is interpreted to provide the meaning of the utterance in the form of keyword-value pair set or feature structures.Context modelling: We have three main objectives for taking into account the contextual knowledge. The first one is to optimise the conceptual decoder process in terms of understanding error rate and running time. The second one is to help the decision module to choose the best solution between all those ones given by the conceptual decoder algorithm. Finally, the third objective is to raise eventual natural language ambiguities of user’s utterances. This point is generally performed on post-processing or in the dialogue module. In this paper we focus on the two first objectives. As it is shown in the figure 1, contextual knowledge is used at the conceptual decoder and at the decision level. Contextual knowledge is deduced from the system prompt and from the dialog history. Before to do this modelling, the following hypothesis was formulated: firstly, the user generally answers to the question asked by the system and secondly, the user gives additional information that do not appear in the dialog history and he does not modify information confirmed. This hypothesis will be discussed in the result paragraph.Each system prompt is manually annotated into several sub-questions. For each referential conceptual segment, there are two states of sub-questions: request and confirmation request. For example, the question “When do you go from Paris to Toulouse?” is divided into three sub-questions (confirmation request of departure town, confirmation request of arrival town and question about date). The history dialog is defined by the set of keyword-value pairs at each speech turn. Each keyword-value pair can be empty, full, or full and confirmed. So, the modelling of the contextual knowledge consists in describing for each kind of sub-questions and for each keyword-value pair, which conceptual segments are dynamically preferred or penalized. Actually, the probabilities of conceptual segments answering the questions asked by the system are increased. In the same way, contextual knowledge deduced from the history dialog allows the probabilities of concerned conceptualFIGURE 1. CACAO Architecturesegments to be modified: probabilities of conceptual segments involving information that the user does not talk yet are increased, and probabilities of conceptual segments involving information already given and confirmed are decreased.The same pragmatic predictions were used in (6) at the speech recognition level to increase the overall score for predicted hypothesis of the recognition system in order to compensate lower recognition score. Now we will discuss the results that were produced with and without context for the two conceptual decoders algorithms: A* and VITERBI.RESULTS AND DISCUSSIONApplication: The application domain concerns a train schedule inquiry application. The DEMON platform (8), a real time spontaneous speech dialogue system in the framework of ARISE LE3-4229 project (Automatic Railway Inquiry Systems for Europe) (9) was developed with the automatic speech tools of PHILIPS for French language. The DEMON system gives over the phone actual timetable information for the connection of the 600 most frequently asked for French train stations. We will use the dialogue corpora obtained during real trials (around 7000 speech turns). From the conceptual analysis of the train schedule inquiry application, 29 conceptual segments were identified. Then the language model was trained on 4268 utterance orthographic transcriptions segmented manually according to the conceptual model of the application. This training is independent of the contextual knowledge.Test protocol: The test corpus contains 2542 utterances extracted from real dialogues recorded through the DEMON platform. Tests were performed from the 5-best solutions produced by the speech recognition module. We do not know the word error rate, so in order to evaluate the performance of our environment, each recognition output were manually analysed by an expert to know if the meaning of the utterance is preserved by the recognition system. This study shows that, if we consider the 5-best solutions, for 28.72% of utterances the meaning is altered and then they cannot be fully understood. Contextual knowledge used for the trials related in this paper, is only relative to the question asked by the system. 2860 speech turns (study corpus) were analysed to qualify the user’s answers (appropriate or not) and to determine which conceptual segments are given by the user according to the prompt. The test corpus is the study corpus without speech turns where the user does not speak (so there are nothing to understand) and speech turns where the answer is considered as irrelevant (for example when the user answers in another language than French). This study shows that the user usually answers to the current system question (75.6%). There are about 10% of speech turns where there is no answer.2.2% of answers include extra information in addition to the answer of the system question and 6.8% not completely answer to the question. There are 3% of ambiguous answers and 2.4% of out-of-topic answers.Tests with A* Algorithm: The A* algorithm finds the N-best conceptual segmentation for a word sequence given at the input, so the decision module chooses between all solutions obtained. An anterior study shown that the number of computed solutions is not significant (utterance error rate is 33.5% for the 1-best solution and 33.1% for the 5-best solutions). The 3-best solutions given by A* was retained for all the tests. A parameter prunes branches of the computed tree. The higher the pruning parameter, the better the results but the process is slower. The figure 2 shows utterance error rate according to the number of branches calculated by the A*algorithm. We can see that if this parameter value is 5, the influence of the context is high: the context reduces the understanding error rate of around 11%. When the parameter value is 10, the influence is less (around 2%) and not significant when the value is greater. We see that the understanding error rate with the value 5 with context is near than the value 10 without context and the running time is less with a low value of the parameter.Tests with Viterbi Algorithm: As the A* algorithm, a parameter can be used in the Viterbi algorithm to optimize the conceptual segmentation. The value of this parameter represents the maximum number of cases computed for each word in the Viterbi matrix. So, the higher the value of this parameter, the better the solution; but the duration of the understanding process is higher. The figure 3 shows utterance error rate according to the parameter value of the Viterbi algorithm without and with context. These results show that only with a low parameter value (5 or 10), the taking into account of the context is significant. When the value parameter is 5, the context reduces the understanding error rate of 10%.Viterbi versus A*:We can see that the utterance error rate obtained with the two algorithms is similar (around 33% for the best results), while the A* algorithm is slower than the Viterbi. The error nature is generally the same with the two algorithms. The best result is 33.2% of utterance misunderstood. This result is acceptable since around 29% of utterances cannot be correctly understood because of recognition errors. This could explain why the influence of the context is not significant when parameter values are high (≥50 for Viterbi and ≥15 for A*). When parameter values of both algorithms are low (5), the results are better for the A* algorithm because it gives several segmentations (here tree) for each solution proposed by the speech recognition module.Discussion:An interpretative hypothesis of the weak effect of the context on the results presented in this paper could be due to a) the domain is strongly task-oriented (only 29 conceptual segments), b) the conceptual segment granularity and c) the non-consideration of the dialog history.CONCLUSIONWe developed an environment for speech understanding, based on a stochastic representation of conceptual entities called CACAO with the Viterbi or A* algorithms. We proposed a model to include contextual knowledge in the speech understanding process. We saw that contextual knowledge can improve weakly the speech understanding process in terms of performance and running time. Other models of conceptual segments and new trials are in progress to measure the effect on understanding rate according to the contextual knowledge.ACKNOWLEDGEMENTSThe authors acknowledge Martine de Calmès to have made available training and testing corpora. 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