The Developmental Origins of the Consonant Bias in Lexical Processing

Abstract

Consonants have been proposed to carry more of the weight of lexical processing than vowels. This consonant bias has consistently been found in adults and has been proposed to facilitate early language acquisition. We explore the origins of this bias over the course of development and in infants learning different languages. Although the consonant bias was originally thought to be present at birth, evidence suggests that it arises from the early stages of phonological and (pre-)lexical acquisition. We discuss two theories that account for the acquisition of the consonant bias: the lexical and acoustic-phonetic hypotheses.

Emergence of a consonant bias during the first year of life: New evidence from own‐name recognition

“…Poltrock and Nazzi (2015) proposed that instead of a strict division between the acoustic‐phonetic and lexical hypotheses, both may play a role in consonant bias emergence (see also Nazzi et al, 2016). Development of speech perception and word learning skills occur at the same time and likely influence one another (Werker, 2018).…”

“…For example, English, Dutch, and Spanish listeners are more likely to change the pseudoword kebra into the real word cobra , conserving consonantal information, than changing it into zebra , conserving vocalic information (Cutler, Sebastián‐Gallés, Soler‐Vilageliu, & Ooijen, 2000; Ooijen, 1996). Such evidence of a consonant bias in lexical processing is thought to reflect the underlying structure of speech and although originally proposed as innate (Nespor, Peña, & Mehler, 2003), recent evidence suggests that infants initially have a bias for vocalic over consonant information during lexical processing (vowel bias; for a review of cross‐linguistic evidence see Nazzi, Poltrock, & Von Holzen, 2016). The emergence of the consonant bias may therefore reflect development of a sophisticated understanding of the speech in an infants’ native language and has been proposed as a bootstrapping mechanism for early language acquisition.…”

“…As development continues, however, the saliency of vowels loses importance to consonants, which are processed more categorically (Fry, Abramson, Eimas, & Liberman, 1962) and therefore provide a more reliable cue to lexical processing. Variation in acoustic/phonetic properties, such as lexical stress which leads to vowel reduction in English or the large number of vowels in Danish, has been suggested to account for the cross‐linguistic variation found in evidence for the consonant bias (Delle Luche, Floccia, Granjeon, & Nazzi, 2016; Floccia et al, 2014; Højen & Nazzi, 2015; see Nazzi et al, 2016 for a review).…”

Second language learners develop non-native lexical processing biases

“…For English-L1 Mandarin-L2 learners and Mandarin-L1 English-L2 learners, lexical processing in an L2 appears to involve adapting a native phonological bias to meet the specific demands of the language, i.e., a C-bias in English and a V-bias in Mandarin. Whereas ample research has documented how a C-bias develops and affects English speakers’ lexical processing (Nazzi et al, 2016; Nazzi and Cutler, 2019), far less research has investigated how a potential V-bias emerges in Mandarin infants and to what degree such a bias affects adult Mandarin speakers’ lexical processing. The present study's word reconstruction results contribute to the small but growing body of evidence documenting how Mandarin (and Cantonese) listeners exhibit a lexically related bias favoring vocalic information rather than consonantal information.…”

“…Languages vary with respect to the proportion of consonants and vowels in the phonological inventory, how these cues are realized in speech, and each cue's relative informativeness across prosodic, syntactic, and lexical levels. These language-specific differences may modulate the functional role of consonants and vowels (Højen & Nazzi, 2016; Nazzi et al, 2016; Floccia et al, 2014). For instance, spoken Danish exhibits a relatively high degree of consonant lenition (Pharao, 2011; Grønnum, 1998; Basbøll, 2005), which increases the informativeness of Danish vowels.…”