The contrast between word-initial [n] and [l] is disappearing in many Chinese languages, including Eastern Min. Before investigating the status of the merger, we need to identify the acoustic cues that distinguish [n] from [l]. In English and Mandarin, languages with the [n] and [l] contrast, we examined: (1) Duration: consonant duration and consonant-vowel transition duration; (2) Formant frequencies: F1, F2 and F3 at the midpoint of the consonant; (3) Formant intensities: I1, I2, and I3 at the midpoint of the consonant; and (4) Relative amplitude (the amplitude difference between the consonant and the following vowel). Preliminary results show that [n] is significantly longer than [l] in Mandarin and English but not in Eastern Min. F2 of [n] is higher than F2 of [l] in English and Mandarin, whereas the direction is reversed in Eastern Min. Finally, the difference in relative amplitude between [n] and [l] is greater in English and Mandarin than in Eastern Min. Together, these results suggest a merger in progress in Eastern Min . Moreover, older Eastern Min speakers showed the merger to a greater degree than younger speakers, presumably because the older speakers use Mandarin less frequently.

The current study investigated the merger-in-progress between word-initial nasal and lateral consonants in Fuzhou Min, examining the linguistic and social factors that modulate the merger. First, the acoustic cues to the l-n distinction were examined in Fuzhou Min. Acoustic analyses suggested a collapse of phonemic contrast between prescriptive L and N (phonemes in the unmerged system), with none of the six acoustic cues showing any difference across L and N. Linear discriminant analysis did identify acoustically distinct [l] and [n] tokens, although the mapping onto the phonetic space of prescriptive L and N substantially overlapped. Speakers of all ages and both genders tended to produce [l], and low vowels correlated with more [n]-like classification. In perception, AX discrimination data showed Fuzhou Min listeners confused both prescriptive L and N and acoustic [l] and [n]. Greater sensitivity to the acoustic differences occurred in the context of low vowels and a nasal coda, supported by the acoustics of the stimuli, and younger listeners were more sensitive to the difference between [l] and [n] than older listeners. In two-alternative forced choice (2AFC) identification, Fuzhou Min listeners also identified the merged form as L more frequently than N, with more L responses elicited in the context of low vowels and in the absence of nasal codas. Overall, although Fuzhou Min speakers produced some acoustically distinct [l] and [n] tokens in the context of a sound merger, these productions did not map onto prescriptive L and N. In addition, younger listeners were more sensitive to the acoustic distinction than older listeners, suggesting an emerging acoustic contrast possibly arising due to contact with Mandarin.

We identified six acoustic correlates to the phonemic contrast between word-initial [l] and [n] in both English and Mandarin (Cheng and Jongman, 2019, JASA). All six cues suggested the phonemic contrast between prescriptive L and N (phonemes in the unmerged system) disappeared in Eastern Min (EM) in production. The current study investigated the phonological and social factors that modulate the merger-in-progress. In production, a classifier was trained with acoustic parameters from Mandarin (F3, F1 bandwidth, A1-P0) to categorize EM tokens. Linear discriminant results illustrated acoustically distinct [l] and [n] tokens as the phonetic realizations of the merger. Both prescriptive L and N were variably realized as acoustic [l] or [n] in production. Low vowels correlated with acoustically more nasal-like onsets. Speakers of all ages and genders leaned toward [l]. Perceptually, AX discrimination results (ISI = 750 ms) suggested EM speakers did not distinguish prescriptive L from N (mean A′ = 0.46), providing converging evidence of the merger. EM listeners did not perceive the difference between acoustic [l] and [n] either (mean A′ = 0.47). However, lower vowels with nasal codas illustrated a higher degree of sensitivity than other phonological conditions, which was an effect of the larger acoustic distance between stimuli.

In speech perception, when a primary acoustic cue (e.g., VOT) is ambiguous, listeners may increase the weight of a secondary cue (e.g., F0). In experiment 1, we compared the cue-weighting adjustment strategies across younger and older normal-hearing adults with a distributional learning paradigm. Two groups of native English listeners were exposed to voicing contrasts that were ambiguous in either VOT or F0. Additionally, listeners may access lexical information to help resolve the ambiguity in the acoustic signal. Older listeners have been reported to use lexical information to a greater degree than younger listeners. In experiment 2, using a lexically guided learning paradigm, we tested if younger and older adults differ in their use of lexical information when learning to interpret ambiguous acoustic tokens. There were four types of exposure, in which stimuli differed in lexical status ( day-*tay; *doy-toy ) and the acoustic ambiguity involved either only VOT or both VOT and F0. Preliminary results from younger normal-hearing, listeners showed significant speech adaptation effects, with a significant change in cue weights in distributional learning and salient lexical bias in lexically guided learning. More data will be collected from older adults to assess the extent of perceptual learning relative to younger adults.

This study collects production data remotely from speakers of colloquial Beijing in China. Acoustic analysis is conducted to test the surface variation of an underlying falling tone between falling and rising when preceding another underlying fall tone.