Development of [ɹ] in young, Midwestern, American children

Abstract

Beginning at the age of about 14 months, eight children who lived in a rhotic dialect region of the United States were recorded approximately every 2 months interacting with their parents. All were recorded until at least the age of 26 months, and some until the age of 31 months. Acoustic analyses of speech samples indicated that these young children acquired [inverted r] production ability at different ages for [inverted r]'s in different syllable positions. The children, as a group, had started to produce postvocalic and syllabic [inverted r] in an adult-like manner by the end of the recording sessions, but were not yet showing evidence of having acquired prevocalic [inverted r]. Articulatory limitations of young children are posited as a cause for the difference in development of [inverted r] according to syllable position. Specifically, it is speculated that adult-like prevocalic [inverted r] production requires two lingual constrictions: one in the mouth, and the other in the pharynx, while postvocalic and syllabic [inverted r] requires only one oral constriction. Two lingual constrictions could be difficult for young children to produce.

The developmental trajectory of children's perception and production of English /r/-/l/

“…Together, the findings of Dalston (1975) and McGowan et al (2004) suggest that the acoustic features that define /r/, distinguishing it from /l/ and /w/ sounds (namely, F2 and F3 frequencies) are still developing in 3-yr-old children and possibly continue to develop beyond age 3, particularly for /r/ in word-initial position. Three-and 4-yr-old children seem to differentiate /r/, /l/, and /w/ in their productions based on F2 and F3 when they are successfully produced.…”

“…There has been considerable attention directed to the English /l/ and /r/ contrast (the more common American English symbol /r/ is used instead of IPA /ò/ for simplicity) in the speech perception literature and with respect to perceptual cue weighting. Learning this contrast is particularly difficult for some second language learners (e.g., Yamada and Tohkura, 1992;Iverson et al, 2003Iverson et al, , 2005Ingvalson et al, 2011) as well as English speaking children (e.g., Smit et al, 1990;McGowan et al, 2004;Dalston, 1975). Perhaps due to its difficulty for Japanese learners of American English, it is one of the most studied and best understood contrasts for adult cue weighting.…”

“…The distance between F3 and F2 frequencies is likely to highly correlate with F3 and F2. This measure is examined nonetheless given a suggestion that it might be an important feature that defines the /r/ category (McGowan et al, 2004;Stevens, 1998). Clinical studies have shown that important development occurs between 3 and 7 yr old for /l/ and /r/ productions.…”

“…In adult production of /r/, F3 frequency is considerably lower resulting in a small distance between F2 and F3 (Stevens, 1998). The primary interest of McGowan et al (2004) was the differential development of these formant frequencies in different syllabic positions, i.e., prevocalic (e.g., "right"), postvocalic (e.g., "car"), medial syllabic (e.g., "Burt"), and final syllabic (e.g., "doctor") positions. The overall developmental trend was such that both F2 and F3 decreased with age; however, they decreased at different rates depending on the syllabic position.…”

“…More recently, McGowan et al (2004) longitudinally tracked the development of /r/ production in children from 15 to 32 months old, focusing on the changes in F2 and F3 frequencies over time. In particular, the authors examined the distance between F2 and F3 as an important acoustic cue for /r/.…”