Katherine Demuth

Markedness and the Development of Prosodic Structure

It has long been noted that children’s early words are truncated in form, and that those forms show a certain degree of variability in shape. In this paper I argue that children’s early word productions can best be understood in terms of output constraints on surface form. First, I show that children’s early grammars allow for the emergence of the unmarked form of syllables (Core Syllables) and prosodic words (Minimal Words), and that these can be thought of as different stages of prosodic development. I then demonstrate how the prosodic development of children’s early words can be naturally accounted for in terms of prosodic

Word-minimality, Epenthesis and Coda Licensing in the Early Acquisition of English

Many languages exhibit constraints on prosodic words, where lexical items must be composed of at least two moras of structure, or a binary foot. Demuth and Fee (1995) proposed that children demonstrate early sensitivity to word-minimality effects, exhibiting a period of vowel lengthening or vowel epenthesis if coda consonants cannot be produced. This paper evaluates this proposal by examining the development of word-final coda consonants in the spontaneous speech of four English-speaking children between the ages of one and two. Although there was no evidence of vowel lengthening, coda consonants were more accurately produced in monosyllabic target words with monomoriac vowels, suggesting earlier use of coda consonants in contexts where they can be prosodified as part of a bimoraic foot. One child also showed extensive use of vowel epenthesis and coda consonant aspiration concurrent with the production of codas. However, we show that this was due to the articulatory challenges of producing complex syllable structures rather than an attempt to produce well-formed minimal words. These results suggest that learners of English may exhibit an early awareness of moraic structure at the level of the syllable, but that language-specific constraints regarding word-minimality may be acquired later than originally thought.

Prosodically-Conditioned Variability in Children's Production of French Determiners.

Researchers have long noted that childrens grammatical morphemes are variably produced, raising questions about when and how grammatical competence is acquired. This study examined the spontaneous production of determiners by two French-speaking children aged 1;5-2;5. It found that determiners were produced earlier with monosyllabic words, and later with disyllabic and trisyllabic words. This suggests that French-speaking childrens early determiners are prosodically licensed as part of a binary foot, with determiners appearing more consistently only once prosodic representations become more complex. This study therefore provides support for the notion that grammatical morphemes first appear in prosodically licensed contexts, suggesting that some of the early variability in morphological production is systematic and predictable.

Asymmetries in the acquisition of word-initial and word-final consonant clusters

Previous work on the acquisition of consonant clusters points to a tendency for word-final clusters to be acquired before word-initial clusters (Templin, 1957; Lleó & Prinz, 1996; Levelt, Schiller & Levelt, 2000). This paper evaluates possible structural, morphological, frequency-based, and articulatory explanations for this asymmetry using a picture identification task with 12 English-speaking two-year-olds. The results show that word-final stop+/s/ clusters and nasal+/z/ clusters were produced much more accurately than word-initial /s/+stop clusters and /s/+nasal clusters. Neither structural nor frequency factors are able to account for these findings. Further analysis of longitudinal spontaneous production data from 2 children aged 1;1-2;6 provides little support for the role of morphology in explaining these results. We argue that an articulatory account best explains the asymmetries in the production of word-initial and word-final clusters.

Early syntactic productivity: Evidence from dative shift ☆

The abstractness of childrens early syntactic representations has been questioned in the recent acquisition literature. While some research has suggested that childrens knowledge of basic constructions such as the transitive is robust and abstract at a very young age, other work has proposed that young children only have constructions that are specific to individual lexical items. The present paper seeks to resolve this discrepancy by examining childrens abstract knowledge of the English dative alternation via a production study. The studies ask whether young children who hear a sentence like I pilked the cup to Petey know that the same meaning can be expressed with the sentence I pilked Petey the cup. This generalization is well-attested in the language that children hear and represents a strong test-case for determining the nature of childrens early syntactic representations. The results indicate that three-year-old children have productive knowledge of the English dative alternation, but that their performance can be influenced by small changes in the nature of the task. A preference for the prepositional dative form is also found and the possible reasons for this preference are discussed.

Subject, topic, and Sesotho passive.

Counter to findings in English, German and Hebrew, recent acquisition studies have shown that the passive is acquired early in several non-Indo-European languages. In an attempt to explain this phenomenon, this paper addresses certain typological phenomena which influence the early acquisition of passives in Sesotho, a southern Bantu language. After outlining the structure of the Sesotho passive and its syntactic and discourse functions, I examine Sesotho-speaking childrens spontaneous use of passives, showing that the acquisition of passives in Sesotho is closely linked to the fact that Sesotho subjects must be discourse topics. I conclude that a detailed examination of how passive constructions interact with other components of a given linguistic system is critical for developing a coherent and universally applicable theory of how passives are acquired.

Universality Versus Language-Specificity in Listening to Running Speech

Recognizing spoken language involves automatic activation of multiple candidate words. The process of selection between candidates is made more efficient by inhibition of embedded words (like egg in beg) that leave a portion of the input stranded (here, b). Results from European languages suggest that this inhibition occurs when consonants are stranded but not when syllables are stranded. The reason why leftover syllables do not lead to inhibition could be that in principle they might themselves be words; in European languages, a syllable can be a word. In Sesotho (a Bantu language), however, a single syllable cannot be a word. We report that in Sesotho, word recognition is inhibited by stranded consonants, but stranded monosyllables produce no more difficulty than stranded bisyllables (which could be Sesotho words). This finding suggests that the viability constraint which inhibits spurious embedded word candidates is not sensitive to language-specific word structure, but is universal.

Presentational Focus and Thematic Structure in Comparative Bantu

Locative inversion has often been treated as an unaccusativity phenomenon in languages as typologically different as English and Chichewa (e.g. Bresnan 1990). Yet Bantu languages show some diversity in the thematic structure of verbs that can occur with locative inversion and related expletive/impersonal constructions. This paper provides a detailed examination of locative inversion and expletive constructions in Setswana, showing that this class of presentational focus constructions exhibits morphological, syntactic, agreement, and discourse characteristics that differ from those of Chichewa and other Bantu languages. It shows that these differences, the result of morphological loss during historical change, can best be understood synchronically within a theory of partial information structures (Bresnan 1982).

Verb raising and subject inversion in Bantu relatives

Verb raising and subject inversion have long been topics of theoretical linguistic interest in Romance and Germanic languages, amongst others. Bantu languages also exhibit verb raising and subject inversion, though there has been no comprehensive investigation of these phenomena, nor an explanation of crosslinguistic differences. This paper provides a unified account of verb raising and subject inversion in Bantu languages. It shows that subject inversion in Bantu matrix clauses resembles that found in Romance languages. In contrast, however, verb raising to C (similar to V2 in German matrix clauses) occurs only in embedded relative clauses, and only in some Bantu languages. A natural explanation for these phenomena comes from the fact that verb raising interacts with the prosodic status of the relative complementizer, and that Bantu matrix clauses are IPs not CPs. The paper points to the importance of competing interactions between different aspects of the grammar (e.g. prosodic words, syntax) and provides support for the notion of extended projections (Grimshaw 1993, 1997).

Accounting for Variability in 2-Year-Olds' Production of Coda Consonants

One of the challenges in child language research is determining when children have acquired a particular linguistic structure, and of particular interest is the identification of factors that contribute to variable performance. The purpose of the current study is to better understand the mechanisms underlying childrens variable production of syllable-final (coda) consonants (e.g., moon). Fifteen 2-year-olds were asked to imitate novel words of different phonological shapes. Production accuracy was assessed by comparing coda consonant production in stressed versus unstressed syllables, in word-medial versus word-final syllables, in monosyllabic versus bisyllabic words, and also stop codas versus nasal codas. Children were most accurate at producing codas in monosyllables, and least likely to produce codas in medial unstressed syllables, with no systematic segmental effects. Because existing data cast doubt on purely perceptual accounts of the role of acoustic prominence, we argue that the longer durations of acoustically prominent syllables provide learners with more time to articulate coda consonants, thereby enhancing production accuracy. This article concludes with a discussion of the larger implications of variability in phonological development.