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SUMMARY OF LANGUAGE PROCESSING
A. Psycholinguistics is the field of linguistics study in which researchers investigate the psychological processes involved in the use of language, including language comprehension, language (speech or sign) production, and first and second language acquisition. . B. THE HUMAN MIND AT WORK: HUMAN LANGUAGE PROCESSING Speaking and comprehending speech can be viewed as a speech chain, a kind of brain-to-brain linking, A spoken utterance starts as a message in the speaker’s brain/mind. It is put into linguistic form and interpreted as articulation commands, emerging as an acoustic signal. The signal is processed by the listener’s ear and sent to their brain/mind, where it is interpreted. This means that language processing is more than grammar alone, linguistic performance tries to detail the psychological mechanisms that work with the grammar to permit language production and comprehension. C. Comprehension One of the aims of psycholinguistics is to describe the processes people normally use in speaking and understanding language. The various breakdowns in performance, such as “tip-of-the-tongue” phenomena, speech errors, and failure to comprehend tricky sentences tell us a great deal about how language is processed. o The speech signal In linguistics, speech is a system of communication that uses spoken words (or sound symbols). i. The vibrations of our vocal cords cause variations of air pressure, and sounds we produce can be described in terms of: ii. Fundamental frequency (pitch): How fast the variations of air pressure occur. iii. Intensity: The magnitude of acoustic signal, which is perceived as loudness.
iv. The quality of a speech sound is determined by the shape of the vocal tract:the shape affects how the sound waves travel. D. SPEECH PERCEPTION AND COMPREHENSION Speech is a continuous signal. The speech signal can be broken into strings of: phonemes, syllables, morphemes, words, and phrases. a) The "segmentation problem" - > how do listeners carve up the continuous speech signal into meaningful units? Lexical access, stress, and intonation. b) The "lack of invariance problem" - > how do listeners recognize different speech sounds when they are used in different contexts and spoken by different people? Listeners can normalize their perceptions to account for rate of speech and speaker pitch differences. E. BOTTOM-UP AND TOP-DOWN MODELS a) Top-down processing: proceeding from semantic and syntactic information to the lexical information from the sensory input b) Listeners can predict that if a speaker says the then an NP is coming c) In experiments, listeners seem to make much use of top-down information d) Bottom-up processing moving from the sensory phonetic input to phonemes. Then morphemes, etc. up to semantic interpretation e) Listeners wait to construct an NP until they hear the followed by a noun F. LEXICAL ACCESS AND WORD RECOGNITION In order to discover more about lexical access or word recognition, psycholinguists have devised several experiments: a) Lexical decision - > Task of subjects in psycholinguistic experiments that involve people deciding whether or not a string of letters or sounds is a word. Frequently used words such as car are responded to more quickly than infrequent words such as fig. This leads researchers to believe that frequent words are more easily accessed in the lexicon than infrequent words b) Lexical access experiments show that people retrieve all the meanings of a word. G. SYNTACTIC PROCESSING
Computational linguistics is a subfield of linguistics and computer science that focuses on with the interactions of human language and computers. Computational linguistics includes the analysis of: a) Written texts and spoken discourse b) The translation of text and speech from one language into another c) The use of human (not computer) languages for communication between computers and people d) The modelling and testing of linguistic theories. M. COMPUTATIONAL PHONETICS AND PHONOLOGY Computational phonetics and phonology is concerned with processing speech. There are two sides of computational phonetics and phonology: a) Speech recognition - > Process of analysing the speech signal into its component phones and phonemes, and producing, in effect, a phonetic transcription of the speech. b) Speech synthesis - > Process of creating electronic signals that simulate the phones and prosodic features of speech and assemble them into words and phrases for output to an electronic speaker, or for further processing, as in a speech-generation application.
- SPEECH SYNTHESIS Speech sounds can be reduced to a small number of acoustic components that can be mixed together like a recipe, which is known as formant synthesis: Start with a tone at the same frequency as vibrating vocal folds (higher if a woman’s or child’s voice is being synthesised, lower for a man’s). Emphasise the harmonics corresponding to the formants required for a particular vowel, liquid or nasal quality. a) Add hissing or buzzing for fricatives. b) Add nasal resonances for nasal sounds. c) Temporarily cut off sound to produce stops and affricates. Etc. d) Another approach is known as concatenative synthesis which relies on recorded units from humans that are assembled to form the desired utterance. N. TEXT TO SPEECH Text-to-speech programs converts input text into a phonetic representation (for formant synthesizers) or a representation of whatever units are to be combined (for concatenative synthesizers). Two problems with text-to-speech programs are: A. Homographs that are pronounced differently Complex structural knowledge is required to know whether to pronounce read as [rid] or [rʒd] I have read the book B. Inconsistencies in spelling O. COMPUTATIONAL MORPHOLOGY The processing of word structures by computers is computational morphology. Computers also need to understand morphology and be able to identify morphemes. One strategy would be to compile all the morphological forms of all a language’s words into a dictionary. One method of morphological analysis is called stemming (the process of detecting affixes and stripping them from roots to identify morphemes).
P. COMPUTATIONAL SYNTAX
Computers must also be able to determine syntactic structure. A parser is a program that uses grammar to assign phrase structure to a string of words. a) A top-down parser proceeds by first consulting the grammar rules (use a grammar containing the rules S → NP VP, NP → Det N and so forth) and then examining the input string to see if the first word could begin an S. b) A bottom-up parser looks at the input string first and then finds phrasal categories. c) A transition network composed of nodes (circles) and arcs (arrows) may be used to model syntactic processing.
1. COMPOSITIONAL SEMANTICS Compositional semantics is concerned with 1) producing a semantic representation of the input in the computer and 2) producing natural language to represent meanings. 2. COMPOSITIONAL PRAGMATICS Computers use semantic and pragmatic knowledge to analyze structurally ambiguous sentences. 3. COMPUTATIONAL SIGN LANGUAGE a) Linguists at Boston University are currently working on computer algorithms that will recognize sign language as spoken language can be b) The signer stands in front of a camera and the computer recognizes the distinctive features of sign language such as hand shape, movement, and orientation. 4. COMPUTER MODELS OF GRAMMAR a) Computers can be programmed to model the grammar of language b) This forces linguists to be explicit in formulating the rules grammar c) If the program cannot generate a possible grammatical sentence, then there is an error in the grammar d) If the program generates an ungrammatical sentence, then there is an error in the grammar Q. TEXT AND SPEECH ANALYSIS FREQUENCY ANALYSIS, CONCORDANCES, AND COLLOCATIONS Computers can be used to: a) Do frequency analyses to reveal the most common words in written (the, of, and, to, a, in, that, is, was, he) and spoken (I, and, the, to, that, you, it, of, a, know) American English. b) Do concordances, which specify the location of any particular word and its context. c) Do collocation analyses, which reveals the occurrences of two or more words within a short space of each other in a corpus and provides evidence that the presence of one word in a text affects the occurrence of other words.
- COMPUTATIONAL LEXICOGRAPHY Computational linguists need more information about words and morphemes than just the meanings. a. The culturomic revolution
