Jenna Luque

Rate variation as a talker-specific/language-general property in bilingual speakers

Nonnative talkers tend to exhibit slower speech rates than native talkers at the group level. Here we ask whether individual variation in rate is language-general to the extent that L1 rate is a significant predictor of L2 rate within bilinguals. 62 nonnative English talkers participated in three speech production tasks in both their L1 (14 Cantonese, 14 Mandarin, 11 Korean, 4 Portuguese-Brazilian, 6 Spanish, 13 Turkish) and L2 (English), namely, reading a paragraph, spontaneously answering questions, and spontaneously describing a picture story. Two measurements of rate were automatically extracted from the recordings: speech rate (syllables per second), and articulation rate (syllables per second excluding silent pauses). As expected, L2 speech and articulation rates were overall slower than L1 speech and articulation rates for all tasks. Importantly, L2 speech rates and articulation rates were positively related to L1 speech rates and articulation rates, respectively. There were also significant differ...

Clear speech benefits for perception of center-only and edge-only syllables

Clear speech is a speaking style that has been shown to enhance intelligibility in noise; however, the underlying reasons for this enhancement are less well understood. One hypothesis is that listeners require less acoustic information to identify syllables spoken in clear than in conversational speech, allowing them to make use of briefer dips in fluctuating noise. The present study tests this hypothesis by presenting six /bVd/ syllables (“bead, bid, bed, bayed, bad,” and “bod”), produced in clear and conversational speech styles, to 20 monolingual native English-speaking listeners in a six-alternative forced-choice task. These syllables were modified to present varying portions of the syllable to listeners (20, 40, 60, or 80 ms of the syllable preserved). First, center-only syllables were created, in which acoustic information around the vowel midpoint was preserved. Second, edge-only syllables were created, in which information from the vowel center was silenced and formant transitions preserved, with ...

Perception of conversational and clear speech syllables by native and non-native English-speaking listeners

In a recent study later, but not earlier, learners of English as a second language produced a smaller clear-speech benefit than native English-speaking talkers for vowels produced in six /bVd/ syllables (Rogers et al., 2010, JASA 123, 410–423). The present study compares perception of the same syllables by native and non-native English-speaking listeners. Conversational and clear-speech productions of the target syllables, “bead, bid, bayed, bed, bad,” and “bod,” were selected from three monolingual English speakers who had produced a significant clear-speech benefit in Rogers et al. (2010). The syllables were then mixed with noise at several signal-to-noise ratios (SNRs). Perception of these stimuli by three groups of listeners will be examined: (1) monolingual native English speakers, (2) ‘early’ learners of English as a second language, with an age of immersion (AOI) of 12 or earlier, and (3) later learners of English as a second language, with an AOI of 15 or later. Analyses of results of the six-alte...

Rate variation as a talker-specific property in bilingual talkers

Nonnative talkers tend to exhibit slower speech rates than native talkers at the group level. Here we ask whether individual variation in rate is language-general to the extent that L1 rate is a significant predictor of L2 rate within bilinguals. 62 nonnative English talkers participated in three speech production tasks in both their L1 (14 Cantonese, 14 Mandarin, 11 Korean, 4 Portuguese-Brazilian, 6 Spanish, 13 Turkish) and L2 (English), namely, reading a paragraph, spontaneously answering questions, and spontaneously describing a picture story. Two measurements of rate were automatically extracted from the recordings: speech rate (syllables per second), and articulation rate (syllables per second excluding silent pauses). As expected, L2 speech and articulation rates were overall slower than L1 speech and articulation rates for all tasks. Importantly, L2 speech rates and articulation rates were positively related to L1 speech rates and articulation rates, respectively. There were also significant differences in L2 speech rates and L2 articulation rates depending on L1 background and tasks. However, the positive relationship between L1 and L2 rates still holds with these other effects taken into consideration, suggesting that overall rate variation is partially an individual-specific property that transcends L1 and L2 within bilinguals.

The relationship between first language and second language intelligibility in Mandarin-English bilinguals

Previous research has shown that L1 speech intelligibility, as judged by native listeners, varies due to speaker-specific characteristics. Similarly, L2 speech intelligibility as judged by native listeners also varies across speakers. Given variability in L1 and L2 intelligibility, we hypothesize that, within bilinguals, some speaker-specific characteristics that contribute to variability in L1 intelligibility (e.g., long-term average spectrum, speech rate, and articulatory precision) are language-independent and therefore also contribute to variability in L2 intelligibility. This leads to the expectation that within a group of bilingual speakers, relative L1 intelligibility is a significant predictor of relative L2 intelligibility. In the current study, 14 Mandarin-English bilinguals produced 112 short meaningful sentences in their L1 (Mandarin) and L2 (English). Independent groups of Mandarin and English listeners then repeated back the sentences (native-accented Mandarin productions for Mandarin listen...

English speakers' discrimination of Korean plain versus aspirated affricates

The Korean three-way voicing distinction has been of much interest to phoneticians. Korean obstruents may be plain, tense, or aspirated, which differ in VOT, closure duration, and f0 of vowel onset (Cho et al., 2002; Kim, 1994). Previous research on Korean stops has shown that English speakers perceive all three categories as voiceless in initial position (Shin, 2001). The present study extends this to Korean affricates, which are partly cued by frication duration, an acoustic cue that is distinctive in English for differentiating fricatives from affricates (Repp et al., 1978). Twenty monolingual English speakers participated in the study. The stimuli were six tokens each of the plain and aspirated Korean affricates ([tSa] and [tSha]), naturally produced by a male native speaker of Seoul Korean. Participants completed an AX discrimination task, following five practice trials in which they received feedback on their answers. Results showed very poor discrimination that did not differ from chance (mean d′ =...

Clear speech production by nonnative English speakers

Clear speech is an intelligibility-enhancing mode of communication often used when speakers have trouble being understood. Previous work has established that both native and non-native listeners can receive a clear speech perception benefit, though possibly to differing degrees (Bradlow and Bent, 2002). Few studies have looked at whether nonnative talkers can induce this clear speech benefit (e.g., Smiljanic and Bradlow, 2007; Rogers etal., 2010). The current study examined English clear and conversational speech by nonnative speakers from three language backgrounds (Japanese, Portuguese, and Turkish) and two proficiency levels to determine their effect on the inducement of a clear speech benefit. Native English listeners repeated back semantically anomalous sentences. The signal to noise ratio was adjusted to the level at which they could correctly repeat 50% of the words using an adaptive test similar to the Hearing in Noise Test (Nilsson etal., 1993). The results suggest that the speakers native langu...

A simple hearing screener up to 17 kHz for use in speech perception research.

Speech scientists are well aware that hearing ability affects the perception of speech sounds. However, hearing is rarely directly tested in studies of normal speech perception. Furthermore, standard audiological testing does not test above 8 kHz, although speech spans frequencies as high as 17 kHz. Given that amplification of frequencies above 8 kHz aids speech perception in hearing impaired subjects, higher frequencies appear to play a role in speech perception. Thus, speech perception research would be improved by incorporating direct tests of speech frequency hearing in all participants. We developed a simple, computer‐based hearing screener for use in speech perception research. Using easily accessible equipment and simple calibration techniques, the screener tests bilateral hearing sensitivity between 250 Hz–17 kHz in about 5 min and is easily implemented by non‐audiologists. A total of 111 ears from 56 participants were tested using both the simple screener and a full audiological workup using modi...

Korean‐English bilinguals’ perception of phonetic contrasts in their two languages.

Korean speakers are known to find English /r/‐/l/ difficult to discriminate, and English speakers have trouble discriminating Korean voicing contrasts. We tested Korean‐English bilinguals’ perception of these difficult phonetic contrasts to examine the effects of age of acquisition and language dominance on bilinguals’ perception in their two languages. All bilingual participants were native Korean speakers but varied in age of English acquisition. Some reported English to be their dominant language, while others were Korean‐dominant. Participants completed a 2AFC task in which they were asked to click on one out of a pair of pictures. On key trials the pictures formed a minimal pair (e.g., rock versus lock). The same task was completed once in English (key items contained the /r/‐/l/ contrast) and once in Korean (key items contained the plain versus tense voicing contrast). Earlier exposure to English led to greater accuracy and faster response on the English task. However, neither age of acquisition nor...