Language 1 Structure and Comprehension Lecture Notes PDF

Psychology 240 Language 1 Issues: (a) What are the properties of language? (b) How does language convey meaning? (c) How is language comprehended? Structure of language Language can be basically divided into two tasks: Production (speaking, writing) Com...

Psychology 240 Language 1 Issues: (a) What are the properties of language? (b) How does language convey meaning? (c) How is language comprehended? Structure of language Language can be basically divided into two tasks: Production (speaking, writing) Comprehension (listening, reading). Hierarchy One of the most striking things about language is that different levels are involved in both production and comprehension. Levels are arranged in a hierarchy. Speaking: start with thought/idea make it into a sentence transform the sentence into sounds Listening: hear sounds group them into words make the words into a sentence understand the idea behind the sentence. Mapping between sound and meaning is arbitrary - different languages use different sounds, different words, and different rules for word order. Phonemes Phonemes are the lowest level of the hierarchy; the smallest unit of speech sound. Examples: The = Th + e Bus = B + u + s (length of hiss doesn't matter). Phonemes are units of speech sound that are important in a language: eg, "bus". Three phonemes, but length of the hiss at the end is irrelevant; there is a single phoneme there There are about 40 phonemes in English; similar number in other languages, but languages differ in the ones they use-- Total possible is about 100. (range from 11 in Hawaiian; up to 60 in some African dialects) Phoneme differences in some languages are not significant in other languages. Examples:  L and R sounds not significant in Japanese. Tonal difference significant in Chinese, but pitch doesn't matter in English. Clucking sound is a phoneme for the Xhosa people of South Africa. English doesn't distinguish between aspirated and unaspirated "p". Aspirated is accompanied by a puff of air ("puff"). Unaspirated ("cup") doesn't produce puff. Particular rules of order describe how phonemes can be combined into morphemes. Fpibs is not okay. Pritos is okay. Not just pronounceability however: Tlitos is not okay - English language does not have words that begin with Tl. Specific to English (Tlingit is a Native American language - Pacific Northwest). Speech perception is an impressive feat -- language is spoken at a rate of up to 10 phonemes per second. - can be understood at up to 16 per second Particularly impressive in that phonemes overlap, with few periods of silence, and the pronunciation of one phoneme can alter the pronunciation of the subsequent phoneme. Morphemes. Morphemes are the smallest unit of sound that signals meaning. Corresponds to things we call prefixes, suffixes, roots, or stems. Examples: "s" at the end of a word "run". A morpheme can constitute an entire word but does not have to. Suffix "-s" typically indicates more than one." Prefix "pre-" means before. But the meaning depends on the position. Steam does not mean "more than one team." Words Words are either single morphemes or combinations of morphemes. adults know about 50- 80,000 morphemes, but several hundred thousand words. Strange, stranger, strangers, strangest each counted as separate words. Impressive memory: "abrasive" or "yodel" is less than once per million, but not forgotten. Specific rules say what morphemes can be combined. ("lifted" is ok; "goed" is not) Phrases and sentences Syntax is the name for the system that arranges words together into phrases and sentences. Syntactic rules that determine word order to convey meaning. Phrases are the building blocks of sentences, words alone not enough. A phrase is an organized grouping of words. Phrases organize words into meaningful units:eg, (The French bottle) (smells) vs. (The French) (bottle) (smells). Mean different things: In one case bottle is a noun, and in 2nd case bottle is a verb. Sentence is a group of phrases that conveys a meaning. Meaning In order to understand language then, we have to have some idea of what meaning is. What is it for a word to mean something? The meaning of words Probably the simplest idea is that a word stands for something in the world. But not just reference. Some words have vague referents (justice, truth) but clear meaning. Meaning is the idea or concept expressed; referents are the things in the world that are named by the word. Refer back to discussion of concepts and their organization. Words are represented by features in memory; but the features are not all or none. They are more or less characteristic, and ones with the most characteristic features are the most typical of a concept. Words are also connected to one another by a network. Related to concepts/categories in LTM Words symbolize concepts Meanings of sentences – Words must be grouped into phrases – Appropriate meaning assigned not just by words in isolation, but by relationships between words. The meanings of sentences. To extract a meaning from a sentence, you've got to be able to take the words, group them into phrases properly, and assign each of the words to the appropriate meanings. Chomsky is a linguist who has set the stage for the contemporary study of language. Chomsky proposed an analysis of language that helps to describe how words translate into meaning. In order to see his contribution, first have to talk about something called phrase structure descriptions. Phrase Structure First step in understanding meaning: to talk about the meaning of a sentence, you can create something called a "phrase structure description", which shows how the sentence structure is organized into a hierarchy of phrases. Examples: "The boy hit the ball" [slide] This tree structure shows who the actor is, what the action is, and what receives the action. Thus it helps to determine how the sentence conveys meaning. Problem with relying solely on phrase structure to determine meaning: “The shooting of the hunters was terrible” In cases like this, the phrase structure doesn’t help one to figure out the meaning, because it can mean two things: either the hunters were shot, tragically, or the hunters didn’t do a good job of shooting. "The boy hit the ball" vs. "The ball was hit by the boy" different phrase structures can mean the same thing. Chomsky realized that you need to go beyond this phrase structure description. He postulated two different levels of analysis: Surface structure, and deep structure. Surface structure (also known as, surface phrase structure) The phrase structure that applies to the words as they were actually spoken. The boy hit the ball vs. The ball was hit by the boy. Each has a different surface structure. Deep structure: The fundamental underlying phrase structure from which meaning is derived. Includes the main proposition carried by the sentence plus the attitude that is implied. Transformational Grammar: Includes rules that transform among various surface structures, but preserve the same deep structure. Definitions: Deep structures have some attributes that are noted on the slide, although we are not concerned with you learning these for the purpose of the exam. Rather, they illustrate the kind of information represented in the deep structure. Proposition: says simply what the actor, action, and recipient were. Attitude: describes the stance the speaker adopts toward the proposition: 1) whether the sentence is a question. Did the boy hit the ball? 2) Focus of the sentence Active vs. Passive the ball was hit by the boy vs. the boy hit the ball 3) Whether the sentence negates the proposition. the boy hit the ball vs. the boy did not hit the ball The distrinction between surface structure and deep structure helps to clarify some of the situations we discussed earlier: Paraphrases: sentences with the same deep structure, but different surface structures. Note however that when attitude includes negation, this changes meaning. Ambiguity: Ambiguity occurs when the same surface structure can correspond to one or more deep structures. Ambiguity can take place in a couple of ways. Three types of Ambiguity:  (covered in lecture 17) Ambiguity: Ambiguity occurs when the same surface structure can correspond to one or more deep structures. Ambiguity can take place in a couple of ways. Three types of Ambiguity: Lexical ambiguity Ambiguity can happen when a word can mean two different things: "She drove to the bank." "He was bothered by the cold." Syntactic Ambiguity Can happen when the same sentence has two different surface phrase structure descriptions. Words can be grouped in 2 different ways. Note that for these sentences, the surface structure is not the same for the two sentences. So here, surface structure and deep structure are both different. "they are cooking apples" "I saw a gorilla in my pajamas." "Pat wants to discuss sex with Jerry Springer." Referential Ambiguity Same word/phrase can refer to two different things within a sentence. John grabbed his lunch, sat on a rock, and ate it. Susan told Elizabeth that she had to write a paper. When a bright moon ends a dark day, a brighter one will follow. Comprehension Given the analysis we’ve discussed so far, one task of cognitive psychology is to determine how people can take phonemes, morphemes, words etc. and recover the deep structure of a sentence - how do they extract meaning from the sounds or printed words. Identifying phonemes: McGurk effect: in order to comprehend language, we have to identify the phonemes that we hear. The McGurk effect shows that we use not only the auditoey information, but also the visual information: The phoneme we perceive depends on the lip movements we see at the time. The video shows someone saying “ba”. We hear the sound “ba” when we see the lips making the sound “ba”, but we hear the sound “va” if we see the lips making the “v” sound at the moment we are hearing “ba”. So the brain is combining the auditory and visual information. The phonemic restoration effect: Our brain will fill in a missing phoneme using top-down processing based on the utterance we hear. Audio clip shows the “s” sound covered by a cough. We perceive the “s” sound when the cough covers the silent gap. Taking the cough away and playing the phrase with the silent gap reveals that our brain has filled in the gap with a perceived “s” sounds. (Simliar to the illusory letters effect in the lecture on top-down processing.) Parsing a Sentence: Understanding a sentence requires parsing: determining how to break the sentence up into phrases. We need to establish the syntactic structure of the sentence, which tells us who did what to whom. We tend to make assumptions about what the structure of the sentence is, which helps us to determine the phrase structure that applies to those words. Subject-Verb-Object” assumption. When we hear or read a sentence, we initially assume that the words are in the order “Subject-verb-object” When a sentence violates that assumption, it causes comprehension to be slightly slower, because of the need to go back and re-interpret. “After Mary left Tom cried” - assume “Tom” is the object of “left,” not the beginning of a new clause. When we finally see “cried” we have to go back and reinterpret. Slow with garden path sentences like “After Mary left Tom cried” (have to reanalyze the sentence once we realize that the SVO assumption was wrong.) When we can make use of the word meanings to help us parse the sentence, we will be less dependent on assumptions such as the SVO assumption, because the word meanings can tell us which noun is the subject of the sentence and which is the object. Slobin Experiment: Present active vs. passive sentences: "the cat chases the dog" or "the dog is chased by the cat". Presented with one of two pictures. Had to say whether the picture matched the sentence. Result: Faster to respond "yes" or "no" when given the active sentence than when given a passive sentence. Cat, chase and dog can create sentences in which the cat chases the dog, and when the dog chases the cat. So the semantics don’t help us to understand who is chasing whom. These are known as reversible sentences, when either noun would make sense as the subject. In the case of sentences like that, we depend on SVO strategy to parse the sentence, and are slowed down when the sentence is in the passive voice (violating our assumption). A contrasting case is the non-reversible sentence, In non-reversible sentences, only one of the two nouns would make sense as the subject. "The ice cream was eaten by the doctor." is a non- reversible sentence. It doesn't make sense to say "the doctor was eaten by the ice cream." Passive and active sentences are comprehended equally well for Non-reversible sentences, because we can use the word meanings to understand the sentence and don’t rely only on the SVO strategy. Suggests that syntax isn't as important when the semantic information (word meanings) is enough to figure out what is going on in the sentence. So, no advantage for Subject-Verb-Order when reading non-reversible sentences.