The Acoustic Features and Didactic Function of Foreigner-Directed Speech: A Scoping Review

Acoustic characteristics of infant- and foreigner-directed speech with Mandarin as the target language

The quality of speech input influences the efficiency of L1 and L2 acquisition. This study examined modifications in infant-directed speech (IDS) and foreigner-directed speech (FDS) in Standard Mandarin-a tonal language-and explored how IDS and FDS features were manifested in disyllabic words and a longer discourse. The study aimed to determine which characteristics of IDS and FDS were enhanced in comparison with adult-directed speech (ADS), and how IDS and FDS differed when measured in a common set of acoustic parameters. For words, it was found that tone-bearing vowel duration, mean and range of fundamental frequency (F0), and the lexical tone contours were enhanced in IDS and FDS relative to ADS, except for the dipping Tone 3 that exhibited an unexpected lowering in FDS, but no modification in IDS when compared with ADS. For the discourse, different aspects of temporal and F0 enhancements were emphasized in IDS and FDS: the mean F0 was higher in IDS whereas the total discourse duration was greater in FDS. These findings add to the growing literature on L1 and L2 speech input characteristics and their role in language acquisition.

Studying Conversational Adjustments in Interaction: Beyond Acoustic Phonetic Changes

PURPOSE

We examined which measures of complexity are most informative when studying language produced in interaction. Specifically, using these measures, we explored whether native and nonnative speakers modified the higher level properties of their production beyond the acoustic-phonetic level based on the language background of their conversation partner.

METHOD

Using a subset of production data from the Wildcat Corpus that used Diapix, an interactive picture matching task, to elicit production, we compared English language production at the dyad and individual level across three different pair types: eight native pairs (English-English), eight mixed pairs (four English-Chinese and four English-Korean), and eight nonnative pairs (four Chinese-Chinese and four Korean-Korean).

RESULTS

At both the dyad and individual levels, native speakers produced longer and more clausally dense speech. They also produced fewer silent pauses and fewer linguistic mazes relative to nonnative speakers. Speakers did not modify their production based on the language background of their interlocutor.

CONCLUSIONS

The current study examines higher level properties of language production in true interaction. Our results suggest that speakers' productions were determined by their own language background and were independent of that of their interlocutor. Furthermore, these demonstrated promise for capturing syntactic characteristics of language produced in true dialogue.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.24712956.

Phonetic accommodation in non-native directed speech supports L2 word learning and pronunciation

This study assessed whether Non-native Directed Speech (NNDS) facilitates second language (L2) learning, specifically L2 word learning and production. Spanish participants (N = 50) learned novel English words, presented either in NNDS or Native-Directed Speech (NDS), in two tasks: Recognition and Production. Recognition involved matching novel objects to their labels produced in NNDS or NDS. Production required participants to pronounce these objects' labels. The novel words contained English vowel contrasts, which approximated Spanish vowel categories more (/i-ɪ/) or less (/ʌ-æ/). Participants in the NNDS group exhibited faster recognition of novel words, improved learning, and produced the /i-ɪ/ contrast with greater distinctiveness in comparison to the NDS group. Participants' ability to discriminate the target vowel contrasts was also assessed before and after the tasks, with no improvement detected in the two groups. These findings support the didactic assumption of NNDS, indicating the relevance of the phonetic adaptations in this register for successful L2 acquisition.

Reported Use of Second-Language Speech Accommodation in Everyday Interactions: The Role of Individual Differences

BACKGROUND

Proficient speakers of a language often accommodate less proficient speakers during conversation to facilitate comprehension, but information about factors such as personality and language experience that may shape how speakers perceive accommodation is limited.

PURPOSE

We developed an online questionnaire to clarify the use of speech accommodation in relation to individual differences in anxiety, personality, and English proficiency.

METHOD

Using Qualtrics Panels for recruitment, we surveyed a representative sample of second-language (L2) English speakers (n = 201) and first-language (L1) English speakers (n = 192) across the United States. We report descriptive results in addition to correlations and a factor analysis to assess the perception of accommodation in L2 and L1 speakers.

RESULTS

Only a third of L2 participants reported that L1 speakers change their speech when talking to them, and more than half are frustrated when L1 speakers do not accommodate them. Indeed, a majority of our L1 participants reported that they do not change their speech when talking to L2 speakers. For both groups, measures of anxiety, personality, and L2 proficiency modify results, providing novel evidence on factors that influence L2 accommodation.

CONCLUSIONS

Results suggest that L1 speakers accommodate L2 speakers less frequently than previously reported. The data are discussed under communication accommodation theory.