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than do French and English. Unfortunately, phoneme Phonological and Prosodic discrimination studies with bilingual infants are not abundant, especially those including sensitive meth- Bootstrapping ods such as tracking eye movements or measuring brain responses. Research is yet to demonstrate the Around their first birthday, most infants start pro- full extent of the differences and similarities in how ducing words. However, it is typically not until chil- phoneme discrimination develops in bilingual versus dren have acquired some 50 words in their produc- monolingual children. tive vocabulary that they start combining words into utterances. Early theories of syntactic development— Paola Escudero based primarily on corpus work—were consequently University of Western Sydney developed to account for children’s early (syntacti- cally deprived) utterances. By contrast, more recent See Also: Bilingual Language Development; Bilingualism: work has started to focus on children’s comprehen- Interactions Between Languages; Early Second Language sion of grammatical structures at ages that precede Acquisition; Early Word Learning; Electrophysiology productive evidence of syntactic development. Such Methods in Language Development; Phonological work has suggested that, within their first two to three Development; Perception and Categorization; years of life, infants gain sensitivity to many aspects of Statistical Learning. the syntactic structure of their native language. This sensitivity is thus in place even before children have Further Readings acquired a rich vocabulary that may help them tune Escudero, P. “Speech Processing in Bilingual and into the complexities of the ambient language. Multilingual Listeners.” In The Handbook of Laboratory The relatively early sensitivity to grammati- , A. C. Cohn, C. Fougeron, and M. K. cal structure has raised the question of what cues Huffman, eds. Oxford, UK: Oxford University Press, enable young, preverbal children to acquire . 2011. According to one account, prosodic information, and Escudero, P., T. Benders, and K. Wanrooij. “Enhanced phonological cues more broadly, immediately per- Bimodal Distributions Facilitate the Learning of ceivable from the speech signal, may be the key ingre- Second Language Vowels.” Journal of the Acoustical dient providing infants’ initial bootstrap into the lan- Society of America, v.130 (2011). guage. The central tenet of this hypothesis, typically Kuhl, P. K., K. A. Williams, F. Lacerda, K. N. Stevens, and referred to as the phonological bootstrapping hypoth- B. Lindblom. “Linguistic Experience Alters Phonetic esis, or bootstrapping from the signal, is based on the Perception in Infants by 6 Months of Age.” Science, idea that crude structural properties of are sig- v.255 (1992). naled by their phonological correlates. That is, chil- Maye, J., J. F. Werker, and L. A. Gerken. “Infant Sensitivity dren can learn certain aspects of the structure of their to Distributional Information Can Affect Phonetic language through an analysis of the surface form of Discrimination.” Cognition, v.82 (2002). the incoming speech signal. Because this approach to Polka, L. and J. F. Werker. “Developmental Changes in bootstrapping into one’s native language requires no Perception of Nonnative Vowel Contrasts.” Journal prior linguistic knowledge, it can potentially explain of Experimental Psychology: Human Perception and the earliest steps of . Performance, v.20 (1994). The notion that prosodic information in the Rivera-Gaxiola, M., J. Silva-Pereyra, and P. K. Kuhl. speech stream contains cues to syntactic structure “Brain Potentials to Native and Non-Native Speech was first introduced in the 1980s by researchers such Contrasts in 7- and 11-Month-Old American Infants.” as Lila Gleitman, James Morgan, Elissa Newport, Developmental Science, v.8 (2005). Ann Peters, and Eric Warren and forms the basis of Werker, J. “Perceptual Foundations of Bilingual the current phonological bootstrapping hypothesis. Acquisition in Infancy.” Annals of the New York Originally called the prosodic bootstrapping hypoth- © Brooks, Patricia J.; Kempe, Vera, Apr 22, 2014, Encyclopedia of Language Development SAGE Publications, Thousand Oaks, ISBN: 9781483346434 Academy of Sciences, v.1251 (2012). esis, a term introduced by Steven Pinker, the hypoth- Werker, J. F., K. Corcoran, C. T. Fennell, and C. L. Stager. esis mainly focused on infants’ use of (i.e., “Infants’ Ability to Learn Phonetically Similar Words: information such as pitch modulation and rhythmic Effects of Age and Vocabulary Size.” Infancy, v.3 (2002). variation) to bootstrap into the structural properties 448 Phonological and Prosodic Bootstrapping

of the language. Later accounts also have started prosodic cues correctly identify clause boundaries to incorporate nonprosodic information available approximately 88 percent of the time. from the speech signal, such as phonetic and phono- Of course, a correlation between the prosodic tactic cues. To integrate this broader view, Morgan information and syntactic structure does not imply and Katherine Demuth referred to the phonological that the two are perfectly aligned. Perhaps one of bootstrapping hypothesis, which is currently the most the most frequently raised criticisms of the prosodic commonly used term. bootstrapping hypothesis concerns the caveat that The idea that a purely perceptual analysis of the there is no one-to-one correspondence between pro- speech signal may reveal grammatical structure rests sodic and syntactic . For example, although on a few critical assumptions: that (1) structural prosodic boundaries typically correspond to syn- properties of sentences are reliably correlated with tactic boundaries, the reverse is not necessarily the prosodic or phonetic features; (2) infants are sensitive case. More specifically, while clause boundaries are to the acoustic correlates of these prosodic features; fairly reliably associated with prosodic cues in child- and (3) infants are able to rely on these acoustic cor- directed speech, intermediate phrasal structure has relates of prosodic features during speech perception much weaker prosodic prominence. A sentence such early in life. We here address each of these assump- as He is eating, for instance, is encapsulated in a single tions and discuss the plausibility of the phonological even though the pronoun is a clear syn- bootstrapping hypothesis in more detail. tactic constituent on its own, leaving the major syn- tactic boundary separating the subject from the verb Relationship Between Phonology and Syntax prosodically unmarked. This suggests that not In order for phonology to cue syntax, prosodic and all syntactic boundaries may be learnable from the syntactic phrases need to reliably coincide, and phonological structure. Nonetheless, the phonologi- phrasal prosody should provide language learn- cal information can provide children with the first ers with cues that help them divide sentences into step to decode the signal and can, as such, be used rudimentary prosodic–syntactic units. Prosodic as a first proxy to syntactic analyses. That is, even if units should furthermore be organized hierarchi- some syntactic boundaries will have no clear prosodic cally according to the depth of their acoustic mark- marker, and will hence not be recovered on first pass, ers. Evidence suggests that this is indeed the case. a phonological analysis of the speech signal would Specifically, phonological words are grouped into provide learners with at least some reliable cues that phonological phrases, which in turn constitute into- may guide their early syntactic analysis of sentences. national phrases. Generally speaking, each of these Once bootstrapped, such initial syntactic informa- levels correlates with syntactic levels of utterances, tion can subsequently be used to analyze the input in such that the prosodic structure might provide a a more fine-grained fashion. natural bracketing of speech into syntactically rel- Prosodic phrase boundaries are not the only source evant phrases and clauses. For example, intonational of information infants could access in the speech sig- phrases—corresponding to clauses or propositions nal to cue the syntactic structure. Within phonologi- within a sentence—tend to be universally marked by cal phrases, the position of prosodic prominence is phonological cues such as phrase-initial strengthen- correlated with word order and could thus provide a ing, phrase-final lengthening, pitch declination, and perceptually available surface cue to the typology of pauses. Phonological phrases—intermediate pro- the language. For example, prosodic prominence is sodic phrases, corresponding to syntactic phrases phrase initial in languages where the object follows

typically consisting of a few function and content the verb (e.g., [they] rideV bikesO) and the noun fol-

words—are indicated by similar, but reduced, acous- lows the preposition (e.g., inP storesN), such as Eng- tic correlates. Although the exact set of prosodic lish or French, and is marked by a pitch accent on cues that serve to delimit clauses and phrases differs the initial word. By contrast, prosodic prominence is across languages, a reliable correspondence between phrase final in languages where the object precedes © Brooks, Patricia J.; Kempe, Vera, Apr 22, 2014, Encyclopedia of Language Development SAGE Publications, Thousand Oaks, ISBN: 9781483346434 the prosodic and the syntactic organization is sys- the verb (e.g., bikesO rideV) and postpositions follow

tematically found in both adult- and child-directed nouns (e.g., storesN inP), such as Turkish, Japanese, speech across various languages. For example, corpus or Hindi, and is marked by a longer duration of the work suggests that, in Japanese, much like in English, final word. Sensitivity to phrasal prosodic units may Phonological and Prosodic Bootstrapping 449

thus help infants deduce the syntactic organization for passages containing artificial pauses inserted at of their native language. clause boundaries (e.g., in a great big house / but it A second prosodic cue to the word order of a lan- was sort of dark) over passages containing artificial guage involves the acoustic salience of individual pauses inserted at other, less natural, positions within words. Across a variety of different languages, func- the clause (e.g., in a great big house but it was / sort tion words (frequently occurring words with little of dark). A preference for passages containing pauses lexical meaning, such as , auxiliaries, at the (somewhat less reliable) phrase boundary level and pronouns) tend to be shorter in duration, less (e.g., That / looks great) over passages containing stressed, phonologically reduced, and produced with pauses at other positions in the clause (e.g., That looks lower intensity compared to content words (words / great) emerges by 9 months of age. that are rich in meaning, such as nouns, verbs, and With regard to the sensitivity to phonological cor- adjectives). As function words are situated in initial relates of word order, very young infants—between or final position within a syntactic phrase according 6 and 12 weeks of age—can discriminate sentences to the word order of the language (phrase initial for originating from languages such as French and Turk- verb–object languages and phrase final for object– ish that differ in word order (and its associated pro- verb languages), this acoustic distinction between sodic correlates) but that are otherwise similar in function and content words can help infants derive their phonological properties. Young infants, even the basic word order of their native language. newborns, also experience no difficulty discriminat- ing lists of function words from lists of content words, Sensitivity to Prosodic Features and this ability to tell apart word categories develops The mere alignment of phonological and syntactic into a preference for content words by 6 months of cues, while necessary, is not sufficient for the pho- age, suggesting that the ability to employ this infor- nological bootstrapping hypothesis to hold. In order mation is in place in time to be used for phonological for phonological cues to facilitate the acquisition of bootstrapping. Moreover, even before their first birth- syntactic patterns, children should also be sensitive to day, infants are sensitive to the frequency distribution the phonological manifestation of these cues. It is no of function and content words in their native lan- surprise that adults, with years of experience of lis- guage, leading to expectations regarding the relative tening to their language, are able to identify prosodic position of these items in the input. Such expectations boundaries with great ease. For example, naïve adults are modulated by prosodic cues. Specifically, children can perceptually rank prosodic boundary strengths learning a verb–object order such as French or English even when the lexical content of an utterance is not expect to hear comparatively infrequent words (i.e., accessible. Thus, even in the absence of recognizable the content words) realized with phrase-final promi- words, adults can use acoustic cues to determine the nence (i.e., lengthening) at the end of utterances, prosodic structure of a sentence. But do infants, who whereas children learning an object–verb language have much less experience listening to language, dis- such as Japanese or Hindi expect to hear such infre- play a similar sensitivity? quent items realized with phrase-initial prominence Children are known to process phrasal prosody (i.e., high pitch) at the onset of utterances. Taken from very early on. In fact, infants gain sensitivity to together, these findings of both lines of research make different aspects of prosody with remarkable speed. a strong case for the attunement to prosodic informa- For example, immediately after birth, children dis- tion during early language acquisition. criminate disyllabic strings that differ only in the presence or the absence of a phonological phrase Use of Prosodic Features for boundary. Latí extracted from goríla tísico (with a Language Development phonological phrase boundary) is thus perceived as Infants are thus sensitive to the prosodic features that being functionally different from latí originating from correlate with the structural properties of sentences. gelatína (without the phonological phrase boundary). This suggests that the first two assumptions of the © Brooks, Patricia J.; Kempe, Vera, Apr 22, 2014, Encyclopedia of Language Development SAGE Publications, Thousand Oaks, ISBN: 9781483346434 Furthermore, by 2 months of age, infants are sensi- prosodic bootstrapping hypothesis are met. Recent tive to pitch changes, and a few months later, infants work has further started to address the third assump- begin to display sensitivity to the position of prosodic tion, that infants use the prosodic information they markers in fluent speech, exhibiting a preference have access to during sentence processing. Adults use 450 Phonological and Prosodic Bootstrapping

this information to constrain syntactic analysis. For direct clues to the syntactic labels of constituents (e.g., example, when hearing a homophone such as mort/ noun phrase or verb phrase). To derive this informa- mord (dead/bite), which could either be an adjective tion, syntactic indices such as function words need to (e.g., [le petit chien mort] the little dead dog) or a verb be incorporated. This joint integration of prosodic (e.g., [le petit chien][mord] the little dog bites), adult information and frequently occurring, and acousti- listeners immediately assign the appropriate syntactic cally distinct, function words is central to the lat- category to a word, suggesting that the prosodic orga- est theorized model of phonological bootstrapping. nization of the sentence helps parse sentences into Anne Christophe and colleagues have proposed that syntactic categories. infants could combine these two cues to build a par- How does this ability to utilize prosodic infor- tial syntactic representation of sentences: a syntactic mation online develop during the course of lan- skeleton. In such model, the prosodic boundaries, guage acquisition? Infants have been shown to rap- signaling the syntactic constituent boundaries, would idly employ their early sensitivity to phonological not only aid syntactic processing but also facilitate the information. By 2 months of age, infants’ memory recognition of the function words that are situated at of words is enhanced when they are part of a single the edges of phonological units. clause (e.g., Cats like park benches) as opposed to Function words are crucial in this model because when the words occur in list form without sentence they both promote access to the neighboring content (e.g., Cats. Like. Park. Benches.) or in sepa- word and permit one to categorize the units (verb rate clauses (what cats like. Park benches are). Slightly phrase or noun phrase). For example, a sentence such older infants parse and store syntactic phrases with as The little dog is eating a big bone could be analyzed

much greater ease when they occur in prosodically as [The X]NP [is X-ing]VP [a X]NP, where the prosodic well-formed phrases than when they cross clause or boundaries would be indicative of the syntactic con- phonological phrase boundaries. And as early as by stituent boundaries, the the (typically 13 months of age, infants, much like adults, use pho- occurring before nouns but not before verbs) would nological phrases to constrain lexical access. That is, label the unit as a noun phrase, while the auxiliary children trained to recognize the word form paper is (typically occurring before verbs but not before recognize this word when it has previously occurred nouns) would label the unit as a verb phrase. Even as such within a phonological phrase but not when it without knowledge of any of the content words in straddles a phonological boundary (e.g., [men with the previous sentence, it is possible to compute this the highest pay][perform the most]). In the latter case, partial syntactic representation. Adult studies using children recognize the word pay instead. Moreover, jabberwocky sentences where all content words are

preschoolers use prosodic information to resolve syn- replaced by invented words (e.g., [the moopN] [is

tactic ambiguities (e.g., an ambiguous prepositional- blickingV mabily]) show that the syntactic skeleton attachment sentence such as feel / the frog with the allows adults to determine that moop is a noun, while feather versus feel the frog / with the feather) online. blick is a verb, in less than 500 milliseconds. Studies This demonstrates that children readily employ the examining how young children deal with such newly prosodic features of syntactic structure during sen- created words are currently underway. tence processing and, hence, that all three conditions underlying the plausibility of the phonological boot- Conclusion strapping hypothesis have been met. To what extent can phonological bootstrapping explain the language acquisition process? The find- Syntactic Skeleton ings reviewed here suggest that (1) structural prop- Although the discussion of phonological bootstrap- erties of sentences are reliably correlated with pro- ping has thus far focused on the plausibility of pho- sodic features, that (2) infants are sensitive to the nological bootstrapping on its own, this does not acoustic correlates of these prosodic features, and preclude the possibility that phonological or prosodic that (3) infants are able to rely on these acoustic © Brooks, Patricia J.; Kempe, Vera, Apr 22, 2014, Encyclopedia of Language Development SAGE Publications, Thousand Oaks, ISBN: 9781483346434 cues are processed in tandem with other cues in the correlates of prosodic features during online speech signal. In fact, while the acoustic correlates of syn- perception early in life. At the same time, syntactic tactic structure may boost sensitivity to the grammar information is not always reliably aligned with pro- of the language, on their own, they do not provide sodic information, and by solely attending to the Phonological Awareness 451

phonological information, infants will not be able to Phonological Awareness discover the complete syntactic system of their lan- guage. Nonetheless, phonological bootstrapping may Phonological awareness is the explicit understand- allow the language learner to compute a first, rudi- ing that spoken language comprises discrete linguis- mentary grouping of the input into smaller units, tic units of sound structure, such as words, syllables, roughly corresponding to clauses. Subsequently, and phonemes. Phonological awareness encompasses both phonological cues and other information from a wide variety of skills that indicate an understanding the speech signal, such as the presence of function that spoken language can be analyzed and manipu- words, may further refine these rudimentary group- lated based on the sound structure of words alone, ings into phrase-like units and help detect the basic independent of word meaning. Phonological aware- word order within those units. Other heuristics, such ness primarily develops during the preschool years as syntactic, semantic, or frequency-based boot- and is considered one of the strongest indicators for strapping, may also play roles at this stage. later reading success. Phonological awareness is mea- Taken together, the speech signal presents children sured by tasks along a hierarchy of both linguistic with a window into the syntax of their language. Chil- complexity (e.g., words, syllables, and phonemes) and dren rapidly learn to exploit this information and use cognitive demand (e.g., recognition or manipulation). it to acquire various aspects of the structural proper- Spoken language does not naturally provide acous- ties of their native language. tic cues to distinguish the beginnings and endings of words or individual phonemes in words. Early in devel- Marieke van Heugten opment, infants and toddlers process spoken language Isabelle Dautriche holistically with little awareness that spoken language Anne Christophe comprises discrete words, syllables, and phonemes. Ecole Normale Supérieure Vocabulary expansion is linked to an increased sensi- tivity to individual sounds because of the need to dis- See Also: Distributional Knowledge and Language tinguish between different words with similar sounds. Learning; Grammatical Categories; Lexical Bootstrapping; Children’s awareness of the sound structure of language Multiple Cues in Language Acquisition; Neonatal Speech develops along a predictable continuum from phono- Perception; Parsing/Sentence Processing; Speech Prosody; logical sensitivity to larger units of spoken language . (e.g., words) to phonological sensitivity to the smaller units of sound in language (i.e., phonemes). Further Readings In the early preschool years, children begin to rec- Christophe, Anne, Séverine Millotte, Savita Bernal, and ognize that words comprise individual syllables, and Jeffrey Lidz. “Bootstrapping Lexical and Syntactic as such, they are able to clap or tap out the number of Acquisition.” Language and Speech, v.51 (2008). syllables in various words. This is an important step Gleitman, Lila and Eric Wanner, eds. Language Acquisition: in phonological awareness as it involves parsing words The State of the State of the Art. Cambridge, UK: into segments that, on their own, do not necessarily Cambridge University Press, 1982. carry meaning. For example, the word computer com- Millotte, Séverine, Alice René, Roger Wales, and Anne prises three separate syllables: com, pu, and ter. The Christophe. “Phonological Phrase Boundaries next progression in phonological awareness is devel- Constrain the On-Line Syntactic Analysis of Spoken opment of sensitivity for intrasyllabic word charac- Sentences.” Journal of Experimental Psychology: teristics, such as onset and rime. Onset refers to the Learning, Memory and Cognition, v.34 (2008). beginning consonant (or cluster of consonants) that Morgan, James and Katherine Demuth, eds. Signal to come before a vowel in a given syllable. Rime is the Syntax: Bootstrapping From Speech to Grammar in Early portion of the syllable following the onset, which typ- Acquisition. Mahwah, NJ: Lawrence Erlbaum, 1996. ically comprises a vowel and any subsequent conso- Soderstrom, Melanie, Amanda Seidl, Deborah nants. For example, in the word boat, /b/ is the onset, © Brooks, Patricia J.; Kempe, Vera, Apr 22, 2014, Encyclopedia of Language Development SAGE Publications, Thousand Oaks, ISBN: 9781483346434 Kemler Nelson, and Peter Jusczyk. “The Prosodic and /ot/ is the rime. Similarly, in the word spoon, /sp/ Bootstrapping of Phrases: Evidence From is the onset, and /un/ is the rime. Multisyllabic words Prelinguistic Infants.” Journal of Memory and have the same number of rimes as syllables. Finally, Language, v.49 (2003). children develop an awareness of the individual