Phonetic enhancement of Mandarin vowels and tones: Infant-directed speech and Lombard speech

Abstract

Speech units are reported to be hyperarticulated in both infant-directed speech (IDS) and Lombard speech. Since these two registers have typically been studied separately, it is unclear if the same speech units are hyperarticulated in the same manner between these registers. The aim of the present study is to compare the effect of register on vowel and tone modification in the tonal language Mandarin Chinese. Vowel and tone productions were produced by 15 Mandarin-speaking mothers during interactions with their 12-month-old infants during a play session (IDS), in conversation with a Mandarin-speaking adult in a 70 dBA eight-talker babble noise environment (Lombard speech), and in a quiet environment (adult-directed speech). Vowel space expansion was observed in IDS and Lombard speech, however, the patterns of vowel-shift were different between the two registers. IDS displayed tone space expansion only in the utterance-final position, whereas there was no tone space expansion in Lombard speech. The overall pitch increased for all tones in both registers. The tone-bearing vowel duration also increased in both registers, but only in utterance-final position. The difference in speech modifications between these two registers is discussed in light of speakers' different communicative needs.

Pitch properties of infant-directed speech specific to word-learning contexts: a cross-linguistic investigation of Mandarin Chinese and Dutch

“…The results showed that the median F0 was higher and F0 excursions were larger in IDS compared to ADS at both ages. Vowels in Mandarin Chinese IDS are hyperarticulated (Liu, Tsao, & Kuhl, 2009;Tang, Xu Rattanasone, Yuen, & Demuth, 2017), but vowels in Dutch IDS show hypoarticulation instead (Benders, 2013). In addition, lexical tones in Mandarin Chinese IDS are hyperarticulated (Han, de Jong, & Kager, 2018a;Tang et al, 2017).…”

Lexical Tones in Mandarin Chinese Infant-Directed Speech: Age-Related Changes in the Second Year of Life

“…However, it should be noted that this line of research typically relies on a rather small set of stimuli due to the practicalities of testing children. For example, Kuhl et al (1997) used one target word per vowel; Liu et al (2007) had twelve syllables for four tones, but they only included “the first two clear tokens of each target word”; Tang et al (2017) also used one syllable for each tone. Even though there has been some agreement on the salience of tone hyperarticulation in the first year of life, it has not been established that tone hyperarticulation is present across the board.…”

“…Second, enhancement of tonal contrasts is a possible indicator of tone hyperarticulation in IDS. Such enhancement can be measured by comparing the pitch differences between tone pairs in ADS and IDS, or indicated by a larger tone triangle in IDS (e.g., Tang et al, 2017 , to review later). To date, only a handful of studies have looked at lexical tones in IDS.…”

“…They found that tones in Cantonese IDS had higher F0 and longer duration than tones in ADS, but such differences did not seem to facilitate adults’ perception of tonal contrasts. Using the tone triangle measure in Xu Rattanasone et al (2013) , Tang et al (2017) examined tone hyperarticulation in Northern Mandarin. Interestingly, they only found tone hyperarticulation (for both tone space and duration) when the target tones were in utterance-final position.…”

How Do Infants Disaggregate Referential and Affective Pitch?

“…Infants' environments are rich in affective content, as infant-directed speech (IDS) is characterized by exaggerated pitch contours reflecting “free vocal expression of emotion” (Trainor et al, 2000 ), which attracts infants' attention (Cooper and Aslin, 1990 ; Werker et al, 1994 ), yet does not a priori facilitate tone acquisition, as it may partially obscure contrastive shapes of tones (Papoušek and Hwang, 1991 ; Kitamura et al, 2002 ). Pitch exaggeration in IDS may be partly compensated by tonal hyper-articulation (Liu et al, 2007 ; Xu Rattanasone et al, 2013 ; Tang et al, 2017 ), yet to what extent precisely is an open issue. In order to facilitate disaggregation of referential and affective pitch, young infants may draw on their ability to recognize vocal and visual expression of affect.…”