Perception and Acquisition of Linguistic Rhythm by InfantsEmergence of speech segmentation procedureExperiments that have studied infants’ ability to discriminate languages between birth and 5 monthsShow an evolution of infants’ language discriminations between birth and 5 monthsIntroductionFocus of present paper is on issue of segmentation of fluent speech into wordsMore particularly on development of speech segmentation involves language-specific phonological proceduresSegmentation task has to be different for infant who, starting with no lexicon and no language-specific phonological knowledge, has to discover words in input and learn speech segmentation procedure appropriate to language to be learnedSpeech segmentation emerges between 6 and 7.5 monthsYoung American infants are sensitive to different kinds of potential word-boundary markersAllophonic information – speech sounds that represent single phonemePhonotactic information – study of rules governing phoneme sequenceProsodic/metrical information – patterns of stress and intonation (pitch) of languageSensitivity to allophonic differences found at 2 monthsShown by emergence of preference for legal or frequent sequences of phonemes in native languagePreference for words with predominant English strong-weak stress pattern emerges between 6-9 months10.5 month-old can rely on allophonic cuesAbility to retrieve familiar words from fluent speech found to depend on stress patternProcessing advantage of strong-weak words might result from specification of predominant stress pattern of EnglishBetween 7.5 and 10.5 months, infants would become sensitive to (language-general) distributional properties of syllables in speech stream, which would then allow them to segment weak-strong words by grouping two syllables togetherOnset of word learning/segmentation is under influence of language-specific segmentation procedures, particularly in native languageExistence of independent mechanism for acquisition of metrical segmentation procedureSpeech segmentation is influenced by metrical system of native languageEach procedure is based on metrical unit characteristic of particular languageSegmentation procedures used in English are guided by information about typical word stress patterns as opposed to the syllable that appears to be the unit of segmentation for French, Spanish and Catalan-speaking languagesAdults’ segmentation procedures appear to be deeply embedded in their language-specific competence and acquired at very young ageOnce they have mastered particular language, adults rely on procedures appropriate to that language even when listening to foreign languageSpanish-speaking professor speaking English uses Spanish tactics (different stress patterns) to pronounce English wordsEach of different types of metrical segmentation procedures is optimally adapted to processing of particular rhythmic class of languagesOur proposal is that infants’ sensitivity to rhythm at utterance/suprasegmental level will allow them to specify type of rhythm of native language and develop procedure appropriate to segmentationInfant hears various rhythm of language and uses that rhythm to develop speech segmentationNeed to demonstrate that there are acoustic correlates to rhythmic classesNeed to determine that infants sensitive to rhythmic class info and that this sensitivity plays role in acquisition of segmentation procedures2. Language discrimination at birthEarly language discrimination was based on recognition of native language rather than on rhythmic class discriminationNewborns might be able to discriminate between 2 foreign languagesInfants rely on rhythmic differences when discriminating languagesFirst study used cross-linguistic approach in which different sets of languages were presented, allowing for systematic variation of rhythmic distanceSecond study used an acoustic approach2.1 The role of rhythm – crosslinguistic approach4 different speakers of each language recorded 10 different sentences eachRhythmic distance between languages systematically variedRationale of this experiment was to show that one could determine whether or not infants would perceive language change by using same four languages but varying the way they were pairedNewborns discriminated languages only when there was rhythmic basis for doing so2.2 The role of rhythm – an acoustic approachOne needs to be sure that infants did not attend to some other non-rhythmic speech cue which would define partition of languages used in previous studies equivalent to rhythmic classesSaltanaj manipulation – consisted in replacing each phoneme by just one exemplar of same manner of articulation without modifying durationFor 2 languages considered, intonational differences cannot by themselves explain newborns ability to discriminate between themCo-variation between rhythm and intonation enhances discrimination abilities2.3 SummaryNewborns discriminate languages based on rhythmic properties at utterance levelInfants are, very early on, sensitive to rhythm and their sensitivity allows them to separate languages into classes of languagesSupports language discrimination at birthInfants’ acquisition of metrical segmentation procedure appropriate to processing of native language might rely on early sensitivity to rhythm3 Acquisition of rhythmic properties of native languageRhythmic class acquisition hypothesis – infants’ initial sensitivity to rhythmic classes would allow them to specify common rhythmic properties of native rhythmic class, from which they would develop associated metrical segmentation procedureNative language acquisition hypothesis – newborns’ sensitivity to rhythmic classes might lead to acquisition of rhythmic properties of native languageAbility to discriminate languages evolves during first months with emergence of ability to discriminate native language from foreign language belonging to native rhythmic classMaturation hypothesis – infants should discriminate any 2 languages, provided that they differ sufficiently at acoustic level2-4 month old infants can discriminate native language from foreign languageTested ability of 20-3 month olds English infants to discriminate between 3 pairs of languageResults of 2 of the languages showed close but non-significant discrimination which suggests that infants might be at transitional age – some starting to distinguish native languageStudying discrimination abilities of English-learning American 5