Human speech and birdsong have numerous parallels. Both humans and songbirds learn their complex vocalizations early in life, exhibiting a strong dependence on hearing the adults they will imitate, as well as themselves as they practice, and a waning of this dependence as they mature. Innate predispositions for perceiving and learning the correct sounds exist in both groups, although more evidence of innate descriptions of species-specific signals exists in songbirds, where numerous species of vocal learners have been compared. Humans also share with songbirds an early phase of learning that is primarily perceptual, which then serves to guide later vocal production. Both humans and songbirds have evolved a complex hierarchy of specialized forebrain areas in which motor and auditory centers interact closely, and which control the lower vocal motor areas also found in nonlearners. In both these vocal learners, however, how auditory feedback of self is processed in these brain areas is surprisingly unclear. Finally, humans and songbirds have similar critical periods for vocal learning, with a much greater ability to learn early in life. In both groups, the capacity for late vocal learning may be decreased by the act of learning itself, as well as by biological factors such as the hormones of puberty. Although some features of birdsong and speech are clearly not analogous, such as the capacity of language for meaning, abstraction, and flexible associations, there are striking similarities in how sensory experience is internalized and used to shape vocal outputs, and how learning is enhanced during a critical period of development. Similar neural mechanisms may therefore be involved.

/pdf/birdsong-and-human-speech-common-themes-and-mechanisms-39gg3m47d4.pdf

BIRDSONG AND HUMAN SPEECH: Common Themes and Mechanisms

Surveying the terrain a brief historical perspective on language acquisition research early research on speech perception how speech perception develops in the first year the role of memory and attentional processes in the development of speech perception how attention to sound properties may facilitate learning other elements of linguistic organization relating perception to production wrapping things up. Appendix - methodology used in studies of infant speech perception.

https://www.gendocs.ru/docs/18/17604/conv_1/file1.pdf

The discovery of spoken language

A recent report demonstrated that 8-month-olds can seg- ment a continuous stream of speech syllables, containing no acoustic or prosodic cues to word boundaries, into wordlike units after only 2 min of listening experience (Saffran, Aslin, & Newport, 1996). Thus, a powerful learning mechanism capable of extracting statistical informa- tion from fluent speech is available early in development. The present study extends these results by documenting the particular type of statis- tical computation—transitional (conditional) probability—used by infants to solve this word-segmentation task. An artificial language corpus, consisting of a continuous stream of trisyllabic nonsense words, was presented to 8-month-olds for 3 min. A postfamiliarization test compared the infants' responses to words versus part-words (tri- syllabic sequences spanning word boundaries). The corpus was con- structed so that test words and part-words were matched in frequency, but differed in their transitional probabilities. Infants showed reliable discrimination of words from part-words, thereby demonstrating rapid segmentation of continuous speech into words on the basis of transi- tional probabilities of syllable pairs.

/pdf/computation-of-conditional-probability-statistics-by-8-month-290v3tm2md.pdf

Computation of Conditional Probability Statistics by 8-Month-Old Infants

One critical aspect of language acquisition is the development of a lexicon that associates sounds and meanings; but developing a lexicon first requires that the infant segment utterances into individual words. How might the infant begin this process? The present study was designed to examine the potential role that sensitivity to predominant stress patterns of words might play in lexical development. In English, by far the majority of words have stressed (strong) initial syllables. Experiment 1 of our study demonstrated that by 9 months of age American infants listen significantly longer to words with strong/weak stress patterns than to words with weak/strong stress patterns. However, Experiment 2 showed that no significant preferences for the predominant stress pattern appear with 6-month-old infants, which suggests that the preference develops as a result of increasing familiarity with the prosodic features of the native language. In a third experiment, 9-month-olds showed a preference for strong/weak patterns even when the speech input was low-pass filtered, which suggests that their preference is specifically for the prosodic structure of the words. Together the results suggest that attention to predominant stress patterns in the native language may form an important part of the infant's process of developing a lexicon.

/pdf/infants-preference-for-the-predominant-stress-patterns-of-2vwk219199.pdf

Infants' preference for the predominant stress patterns of English words.

Discrimination of 2 German vowel contrasts was examined in English-learning infants of 6-8 and 10-12 months of age using a head turn procedure. The younger infants were better able than the older infants to discriminate the nonnative contrasts, but performance at 6-8 months was below levels that have been reported for nonnative consonant contrasts. A 2nd experiment using a habituation looking procedure showed that 4-month-old infants discriminated both German vowel contrasts, but the 6-month-olds could not. The findings are consistent with previous consonant work, revealing a shift from a language-general toward a language-specific pattern during the 1st year of life. However, that shift begins earlier in development for vowels than for consonants. There is a substantial body of research on developmental differences in discriminatio n of nonnative phonetic contrasts, but the research to date has focused almost exclusively on the perception of consonants. In the present study, we investigated developmental changes across infancy in discrimination of nonnative vowel contrasts. The existing cross-language research suggests that an important part of early language acquisition involves the tuning of perceptual sensitivities to map on to those required in the native language. For example, cross-language studies of consonant discrimination have revealed that young infants can discriminate nearly every phonetic contrast on which they have been tested, including those contrasts that comprise phones that are not used to distinguish meaning in their language-learning environment (for a review, see Best, in press; Werker, 1991). In an early study, Streeter (1976) showed that Kikuyu-learning infants aged 4 months could discriminate the English voiced-voiceless distinction even though it is not used phonemically in their native language. Similar findings have been reported for many other nonnative consonant contrasts (Aslin, Pisoni,

Julie Piwoz

Papers

Perception of acoustic correlates of major phrasal units by young infants.