Copyright © American Speech-Language-Hearing Association From: Early Phonetic and Lexical Development:  A Productivity Approach J Speech Lang Hear Res. 2001;44(3):670-684. doi:10.1044/1092-4388(2001/054) Legend: Consonant use in stable words for children making the referential transition by 15 months (n = 9). Stable words are those words observed at both 15 and 16 months for a given child. A. Mean percentage of stable words based on each child’s specific VMS consonants was .91 vs. all other supraglottal consonants, .09. B. Mean percentage of stable words based on consonants used by any of the children in the words evaluated, including the previously noted supraglottal consonants [p/b], [t/d], [k/g], [s], [m], [n], [l] (in the order traditionally used in phonetic charts, based on place of articulation in the oral cavity [front to back] and on manner of articulation [extent of oral cavity closure]: stop, fricative, nasal, and lateral) as well as the glide [j] and the glottal [h]. Whereas the consonants “counted” as VMS all involve a complete or nearly complete oral closure, the glide [j] is essentially vocalic and occurs in the period before canonical babbling, as does [h]. Where not all tokens of a word included a consistent consonant, the word was considered variable. Use of [p/b] dominates word production: 42% versus less than 10% for any other supraglottal consonant. Date of download: 10/6/2017 Copyright © American Speech-Language-Hearing Association