Prosodic Emphasis Research Articles

Prosody and focus in speech to infants and adults.

Two studies investigated adults' use of emphasis to mark focused words in speech to infants and adults. In Experiment 1,18 mothers told a story to a 14-month-old infant and to an adult, using a picture book in which 6 target items were the focus of attention. Prosodic emphasis was measured both acoustically and subjectively In speech to infants, mothers consistently positioned focused words on exaggerated pitch peaks in utterance-final position, whereas in speech to adults emphasis was more variable. In Experiment 2,12 women taught another adult an assembly procedure involving familiar and novel terminology. In both studies, stressed words in adultdirected speech rarely coincided with pitch peaks. However, in infant-directed speech, mothers regularly used pitch prominence to convey primary stress. The use of exaggerated pitch peaks at the ends of utterances to mark focused words may facilitate speech processing for the infant. Research on features of early linguistic experiences that influence language acquisition has begun to explore the role of prosody in providing the infant with acoustic cues to linguistic structure in the speech waveform. Faced with the problem of discovering the linguistically relevant units in continuous speech, the preverbal infant may take advantage of features that are regularly correlated with such units as words, phrases, and clauses. According to some versions of this prosodic bootstrapping hypothesis (e.g., Gleitman & Wanner, 1982; Morgan & Newport, 1981), infants can exploit the cues routinely available in spoken English to infer the correct units of analysis for the language without requiring special modifications in maternal speech. Other evidence suggests that the characteristic exaggeration of cues in infant-directed speech may indeed be useful to the infant in partitioning the speech stream. When speaking to infants, mothers use more exaggerated vowel lengthening to mark both phrase boundaries (Morgan, 1986) and clause boundaries (Bernstein Ratner, 1986) than when speaking to adults. The finding that infants are sensitive to clause boundaries in infantdirected but not in adult-directe d speech (Kemler-Nelson, Hirsh-Pasek, Jusczyk, & Cassidy, 1989) suggests that the exaggerated prosody typical of mothers' speech (e.g., Fernald & Simon, 1984) increases the salience of acoustic cues to linguistic structure for the preverbal infant. This recent interest in the usefulness of prosody to infants who are learning language has focused mainly on how cues reveal phrase and clause structure. The focus on syntactic rather than lexical units is not surprising, given that most current theories of language acquisition take for granted the

Effects of patient characteristics on delivery of token test commands by experienced and inexperienced examiners

The Token Test usually is administered in live voice in clinical settings. DeRenzi and Vignolo (1962) state that the commands are to be read by the examiner, “. . . speaking with a clear and measured voice, without any special prosodic emphasis.” However, with these instructions, the clinician is free to vary the rate at which the test commands are administered. The possibility that an examiner may vary the rate at which he presents the test commands during the administration of the test is probably irnpoitant, since recent investigations have shown that the rate at which test commands are presented does affect an aphasic individual’s performance. It has been demonstrated that aphasic individuals make fewer errors to spoken commands when the rate of speech is slowed (Gordon, 1970; Parkhurst, 1970; Weidner and Johnson, 1974; Liles and Brookshire, 1975; Salvatore, 1975). During the administration of clinical tests, clinicians are assumed to present the test materials in a consistent manner. That is, it is hoped that clinicians would not be influenced during the test administration by the severity of the patient’s deficit or by his performance during the test. To investigate the possibility that clinicians may be influenced by these variables, two experiments were carried out. The purpose of the first experiment was to determine whether experienced or inexperienced examiners altered their rate of speech when administering the Token Test to low-level and high-level individuals. The purpose of the second experiment was to determine whether clinicians delivered test commands at a