speech production in psycholinguistics


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speech production in psycholinguistics

  2. 2. 2 Introduction: Speech production is a process that begin when the talker formulate the message in his/her mind to transmit to the listener via speech. The next step in this process is the conversion of the message into the message code. This corresponds to converting the message into a set of phoneme sequences corresponding to the sounds that make up the words, along with prosody (syntax) markers denoting duration of sounds, loudness o sounds, and pitch associated with the sounds ( Rabiner& Juang 1993). Although There has been less research on language production than on language comprehension. The investigation of production is perceived to be more difficult than the investigation of comprehension, primarily because it is difficult to control the input in experiments on production. It is relatively easy to control the frequency, imageability, and visual appearance (or any other aspect that is considered important) of the materials of word recognition experiments, but our thoughts are much harder to control experimentally (Harley 2001). Stages of language production: Language production refers to the process involved in creating and expressing meaning through language (Fields, 2004). Scovel (1998) mentions that the production of speech is neurologically and psychologically far more complicated than negotiating a flight of stars, but its intricacy also goes unappreciated until we suffer some linguistic disability to commit a slip of the tongue. In daily conversations, we remain generally unaware of the complexity of our achievement Psychologist tend to divide linguistic phenomena into stages. One of the most influential psycholinguistic model for speech production, developed by levelt (1989) views is as a linear progression of four successive stages : (1) conceptualization, (2) formulation, (3)articulation, (4)self-monitoring. First, we must conceptualize what we wish to communicate. Second, we formulate this thought into a linguistic plan. Third, we execute the plan through the muscles in the speech system. Finally, we monitor our speech, to assess whether it is what we intended to say and how we intended to say it
  3. 3. 3 (1) Conceptualization: Where does the very beginning of any spoken utterance come from? What sparks speech? These are difficult questions to answer partly because we still don’t know enough about how language is produced, but partly because they deal with mental abstractions so vague that they elude empirical investigation. The American psycholinguist David McNeil, however has gone on record with interesting mentalist account of how speech first conceptualized in the human mind. His theory is that primitive linguistic concepts are formed as two concurrent and parallel modes of though. These are syntactic thinking which spawns the sequence of words which are typically think of when we talk about how language is initiated, and linguistic thinking,, which creates a more holistic and visual mode of communication. The former segmented and linear and create strings of syllables, words, phrases and sentences that together make up speech. He latter is global and synthetic and tends to develop the gestures which we naturally use to punctuate and illustrate our conversation. McNeil’s claim, that syntactic thought and imagistic thought collaborate to conceptualize conversations, is quiet convincingly demonstrated by the way in which speech utterances and ordinary gestures seem to be tired and timed together in any conversation E.g. :Person A: where’s my brief case? Person B: there’s your briefcase! Person B points to the brief case the same moment he says there’s. The problem with mentalism is The process of how imagistic and syntactic thoughts are initially conventionalized are unclear. But McNeil offers some plausible evidence by saying that syntactic thought may be generated by beginning with something demonstrative . while imagistic thought might be of some one pointing towards an object Appealing as McNeill hypothesis appear , it is difficult to use his model to explain this first stage of production for: nothing , his attempts to describe how imagistic and syntactic thought are initially conceptualized are
  4. 4. 4 unclear. For another, the illustrations he uses to describe how gestures synchronize with important syntactic breaks in spoken language are difficult to follow . perhaps it can be adequately illustrated by a videotape and not by drawing. (2) formulation: We have seen that the initial stage of conceptualization is so far removed from the words we actually speak and write that it is difficult to determine this phase of production. But at the second stage of speech production, formulation , we move close enough to the e eventual output of the process to allow us to be more precise in our terminology and more convincing in out use of empirical data. .conceptualization is hard to conceptualize, but formulation is much easier to formulate . well over three decades ago , the psychologist karl lshely published one of the first attempts to account for the way speakers sequences string of sounds, words, and phrases together so rapidly and accurately, , lashely gave the following example of how we comprehend spoken sentences. Rapid rightening with his uninjured hand saved from loss the contents of the capsized canoe. Like all native speakers of any language, the listeners were able to readjust their comprehension of this sentence. After they recognized they had initially wandered down the wrong garden path of comprehension, they were forced to retrace their steps, and to choose the proper path towards complete understanding. Thus lashely was able to demonstrate many of the themes which were central to this seminal essay on speech production. First, he showed how slips of the tongue (or the computer keyboard) provide vivid insights into our understanding of how speech is formulated. Second, he illustrated the power of priming in guiding the direction of speech production. The way we demonstrate how both the production and the comprehension of speech is largely a linear process . people tend to produce and comprehend sentences in a linear way, and for comprehension , each additional piece of
  5. 5. 5 information we receive has the potential to force us to remap out understanding of what we have already heard. (3) Articulating: Once we have organized our thoughts into a linguistic plan, this information must be sent from the brain to the muscles in the speech system so that they can then execute the required movements and produce the desired sounds. Obviously,a thorough explanation of articulatory processes would be too extended. However, it is useful to understand certain basic aspects of articulation which is usually performed within three processes:  Three system of Muscles: Fluent articulation of speech requires the coordinated use of a large number of muscles. These muscles are distributed over three systems: the respiratory, the laryngeal, and the supralaryngeal or vocal tract. The respiratory system regulates the flow of air from the lungs to the vocal tract. The laryngeal system consists of the vocal cords or vocal folds .This system is responsible for the distinction between voiced and unvoiced sounds. E.g. [b] vs [p] (Ladefoged, 1976). The muscles in and around the laryngeal region produce these changes by manipulating the length, thickness, and tension of the vocal cords. This, in turn, significantly influences the fundamental frequency of the sound that results. In particular, the larynx seems to be involved in the increase in frequency that occurs at the end of yes/no questions such as Did Tom mow the lawn? (Lieberman, 1967). The supralaryngeal system consists of structures that lie above the larynx, including the tongue, lips, teeth, jaw, and velum. These structures play a significant role in the production of speech by manipulating the size and shape of the oral cavity (the mouth and pharynx) and the nasal cavity. All of the structures involved in speech production have other functions. The main function of the respiratory system is, of course, breathing. The teeth and
  6. 6. 6 tongue are used to chew and swallow food. The larynx operates as a valve, controlling the air- flow to and from the lungs and preventing food from entering the lungs. Aitchison (1998) stress the dramatic change of the larynx or the ‘voice box’ which houses our vocal cords, like all other speech organs , the larynx did not initially evolve with the specific function of helping human to articulate language.. for one thing, the vocal cords in all animals possessing a larynx serves as a kind of emergency trap door which can prevent foreign matter, such as bit of foods, from falling from he mouth down the pharyngeal tube and through the trachea into the lungs. Lennenberg and others have documented several speech-enhancing characteristics of the voice box that are unique to human and are absent in other mammals, . The most striking difference between humans and all other animals in this area of the body is in the position of the larynx. The advantage of the lower voice box is to embellish the articulation of speech arrangement . unlike other animals the pharynx benefit the production of speech in at least two ways; it creates a new source of speech sounds, a pharyngeal tube also increase resonance by adding extra acoustic space to the already existing oral and nasal cavities . another enormous benefit is the way it frees up the back of the tongue so that the root can maneuver and create more speech sounds However, when these structures are used to produce speech, the pattern of coordination is different. A major challenge for speech researchers is to explain how so many different muscles are coordinated so smoothly during the production of speech.  Motor Control of Speech: begins with motor commands from the brain. As we assemble a linguistic plan for our utterance, the brain structures responsible for speech production send messages to the muscles in the respiratory, laryngeal, and supralaryngeal systems. It is generally believed that these motor commands to speech muscles take the form of commands for the articulators (tongue, lips, and so on) to move to a particular location. If the next phonetic segment is [b], the muscles controlling the lips must be brought into action.
  7. 7. 7 One way to think of the motor commands, then, is that they specify a series of target locations in the vocal tract. It is a simplification, however, to view articulation as the production of a series of discrete sounds. Recall the concept of coarticulation, The phenomenon refers to the condition that the shape of the vocal tract for any given sound often accommodates to the shape needed for surrounding sounds. This typically occurs for upcoming sounds (anticipatory coarticulation) but also may occur when a sound is influenced by previous sounds(perseveratory coarticulation). The result of coarticulation is the undershooting of targets. When an articulator, in anticipation of an upcoming sound, aims for a given location, it does not actually achieve it. The main reason appears to be the distance the articulators must travel to reach a series of rapidly changing targets. When sounds are produced individually, the targets are reached; but when they are articulated in a phonetic context, particularly one that involves antagonistic movements, articulatory undershooting occurs (Sussman & Westbury, 1981).  Planning and Production Cycles: Several studies have converged on the conclusion that we alternate between planningspeech and implementing our plans. Consider first a study performed by Henderson, Goldman-Eisler, and Skarbek (1966), who analyzed the hesitations and fluent speech of individuals being interviewed. Henderson and his colleagues found that all of the participants showed a cycle of hesitation and fluency, although the ratio of speech to silence varied among speakers. These results are consistent with the notion that we plan our utterances in cycles We express a portion of our intended message, pause to plan the next portion, articulate that portion, pause again, and so on (Beattie, 1983). One underlying reason that we tend to hesitate during speech production is that linguistic planning is very cognitively demanding, and it is difficult to plan an entire utterance at once (Lindsley, 1975). As a consequence, we typically plan only a portion of an utterance at a time. Levelt (1983) found that pauses occurred more often before low-frequency words than before high frequency words. Another variable that influences lexical retrieval, and therefore pauses during speech, is the sheer number of words from which we choose. Schacter, Christenfeld, Ravina, and Bilous
  8. 8. 8 (1991) found that during lectures humanists used more filled pauses (such as uh, ah, or um) than social scientists or natural scientists.According to Schacter and his colleagues, the humanities have a far richer vocabulary than the sciences. A different kind of variable that influences lexical retrieval during speech production is the use of gestures. gestures that accompany speech may help speakers formulate coherent speech by facilitating the retrieval of elusive words from the internal lexicon. Gestures are more common in spontaneous speech than in rehearsed speech (Chawla & Krauss, 1994) and more common with speech that contains concrete and spatial words, such as adjacent, cube, and spin (Rauscher, Krauss, & Chen,1996). In addition to word frequency and size of vocabulary, such variables as morphological complexity, lexical ambiguity, age of acquisition, and recency of usage (that is, priming) also influence retrieval. We have been talking of planning and production cycles as being in strict alternation, but sometimes they overlap. Building on the work of Lindsley (1975), Griffin (2001, 2003) has explored the circumstances under which we articulate the beginnings of sentence while planning later parts. A later study (Griffin, 2003) extended this line of thought. Speakers were presented with line drawings and were asked to name the objects without pausing between the names of the two objects (for example, windmill-carrot). It thus seemed that speakers’ response times were sensitive to the fact that they could prepare the second noun (such as carrot) while articulating the first, but only if the first noun was two syllables. In short, we again see that speakers can maintain fluent speech by preparing later portions of their sentences on the fly. (4) Self-monitoring: From time to time, we spontaneously interrupt our speech and correct ourselves. These corrections are referred to as self-repairs. According to Levelt (1983), self-repairs have a characteristic structure that consists of three parts:
  9. 9. 9 First, we interrupt ourselves after we have detected an error in our speech. Second, we usually utter one of various editing expressions. These include terms such as uh, sorry, I mean, and so forth. Finally, we repair the utterance. Let us consider each in turn. Levelt (1983, 1989) distinguishes among three types of repairs. Instant repairs consist of a speaker’s retracing back to a single troublesome word, which is then replaced with the correct word -Again left to the same blank crossing point—white crossing point. In anticipatory retracings, the speaker retraces back to some point prior to the error, as in -And left to the purple crossing point—to the red crossing point. Finally, in fresh starts, the speaker drops the original syntactic structure and just starts over, as in -From yellow down to brown—no—that’s red. In general, speakers repair their utterances in a way that maximizes listeners’ comprehension. The listener’s problem when a speaker errs is not only to understand the correction but also how to fit the correction into the ongoing discourse (Clark & Clark, 1977). Fox Tree and Schrock (1999,295) suggest that speakers use oh to signal to their interlocutors that the conversation is about to change direction. Sometimes oh is used as a sudden reaction to new or surprising information, such as a surprise recollection or a surprise offer. As we have already seen, it may also be used to indicate that the speaker is choosing what to say next, or hedging .  Self-Interruptions: Nooteboom (1980) examined a corpus of 648 speech errors and made several interesting discoveries: -He found that (64%) of the errors were corrected. Some errors were more likely to be corrected than others; anticipations were corrected more often than perseverations. In addition, Nooteboom found that most interruptions occurred very shortly after the error. Nooteboom suggests that the timing of self-interruption after detection of an error is based on two competing forces. On one hand, we have an urge to
  10. 10. 10 correct the error immediately. On the other hand, we want to complete the word we are speaking. Editing Expressions Although the matter could use further study, it appears that the editing expression conveys to the listener the kind of trouble that the speaker is correcting. James (1972) analyzed utterances containing expressions such as uh and oh, suggesting that these convey different meanings. -I saw . . . uh . . . 12 people at the party. -I saw . . . oh . . . 12 people at the party. Du Bois (1974) has also analyzed several different editing expressions as in: (22) Bill hit him—hit Sam, that is(a potentially ambiguous referent). (23) I am trying to lease, or rather, sublease, my apartment(nuance editing). (24) I really like to—I mean, hate to—get up in the morning( true erros). These different editing expressions are not fully interchangeable and that the expression that is used conveys the type of editing that the speaker is doing. Levelt (1989) suggests that the expression uh may differ in some respects from these other expressions, it is a symptom of trouble rather than a signal with a specific communicative meaning. Speakers may simply utter uh when they get stuck in the middle of their utterances. If it does not convey a specific meaning, why say it at all? Perhaps uh, along with various nonverbal cues such as averting one’s gaze, indicates to the listener that the speaker still has the floor. Speech production as a full process: To summarize how the level model works, production begins with a set of ideas that the speaker wishes to express; the abstract level or the conceptual preparation. The next step is that those ideas are tied to lexical concepts because language may have specific words for some of the ideas, but may require combinations of words to express other ideas. After a set of lexical concepts has been activated. Lemmas that corresponds to those lexical concepts become activated, activating lemmas
  11. 11. 11 provide information about morphological properties of words including information about “how words can be combined’’, after a set of morphemes has been activated and organized into a sequence. The speech sounds of the phonemes required can be activated and placed in a sequence. Phonological encoding involves the activation of a metrical structure and syllabification organizing a set of phonemes into syllabized group, whether the specific phoneme comes from the same group or not. The outcome of this process is a set of phonological words consisting of sequence of syllable sized frames, during phonetic encoding, the speech production system consults sets of representations of specific syllables. The system activates the appropriate syllable representations and places them in the appropriate positions in the frame. This representation is used by the motor system to create phonetic gestural score which is the representation used by the motor system to plan the actual muscle movement articulation that will create sounds that the listener will perceive as speech. -concepts point you to lemmas. -lemmas point you to morphological information you need to combine lemmas into larger phrases Morphological encoding point you to speech sounds (phonemes). -you need to express specific set of lemmas in specific forms. Evidence for weaver ++ -comes from three kind of studies: -speech errors. -tip of the tongue experience e(TOT). -picture naming and picture-word inferences studies (Traxler, 2012). Insights from sign language : Here in the final section we look at the production of sign language. The production of signs is important theoretically because it gives us an opportunity to disentangle the cognitive processes involved in translating thought into language from the physical characteristics of our speech apparatus. Speech shares the vocal channel with respiration; in contrast, sign production can occur entirely in parallel with, and unimpeded by, respiratory activity. Thus, consideration of sign production in comparison with speech production can yield insights into some of
  12. 12. 12 the biological limits on linguistic form (Bellugi & Studdert-Kennedy, 1980).One striking similarity is that errors occur in signing that strongly resemble those found with speech.  Independence of Parameters.  Morpheme Structure Constraints. Studies of production rate, in contrast, reveal differences between the two modes. Speakers achieve differences in speech rate primarily by varying the number of pauses, whereas signers vary the duration of signed segments and both the duration and number of pauses. These dissimilarities reflect the effects of respiratory functioning on speech but not on signs. References:  Aitchison, J. (1998). The articulate mammal: An introduction to psycholinguistics. London: Routledge.  Caroll, D. (2003). Psychology of language,6th ed.Thomson Wardsworth, Canada.  Fields, J. (2004). Psycholinguistics: the key concepts. London: Rutledge.  HARLEY, T. (2001). The Psychology of Language. Sussex: Psychology Press.  Ladefoged, P. (1976). A course in phonetics. Newyork.  Lieberman, P. (1967). Intonation, perception, and language. Cambridge: M.I.T. Press.  Rabiner, L. R., & Juang, B. H. (1993). Fundamentals of speech recognition. Englewood Cliffs, N.J: PTR Prentice Hall.  Scovel, T. (1998). Psycholinguistics. Oxford: Oxford University Press.  Traxler, M. J. (2012). Introduction to psycholinguistics: Understanding language science. Chichester, West Sussex: Wiley-Blackwell