Midam Kim

The wildcat corpus of native-and foreign-accented english: Communicative efficiency across conversational dyads with varying language alignment profiles

This paper describes the development of the Wildcat Corpus of native- and foreign-accented English, a corpus containing scripted and spontaneous speech recordings from 24 native speakers of American English and 52 non-native speakers of English. The core element of this corpus is a set of spontaneous speech recordings, for which a new method of eliciting dialogue-based, laboratory-quality speech recordings was developed (the Diapix task). Dialogues between two native speakers of English, between two non-native speakers of English (with either shared or different L1s), and between one native and one non-native speaker of English are included and analyzed in terms of general measures of communicative efficiency. The overall finding was that pairs of native talkers were most efficient, followed by mixed native/non-native pairs and non-native pairs with shared L1. Non-native pairs with different L1s were least efficient. These results support the hypothesis that successful speech communication depends both on the alignment of talkers to the target language and on the alignment of talkers to one another in terms of native language background.

The Wildcat corpus of native‐ and foreign‐accented English

This paper describes the development of the Wildcat Corpus of native- and foreign-accented English,a corpus containing scripted and spontaneous speech recordings from 24 native speakers of American English and 52 non-native speakers of English.The core element of this corpus is a set of spontaneous speech recordings, for which a new method of eliciting dialogue-based, laboratory-quality speech recordings was developed (the Diapix task). Dialogues between two native speakers of English, between two non-native speakers of English (with either shared or different LIs), and between one native and one non-native speaker of English are included and analyzed in terms of general measures of communicative efficiency.The overall finding was that pairs of native talkers were most efficient, followed by mixed native/non-native pairs and non-native pairs with shared LI. Non-native pairs with different LIs were least efficient.These results support the hypothesis that successful speech communication depends both on the alignment of talkers to the target language and on the alignment of talkers to one another in terms of native language background.

Phonetic accommodation after passive exposure to native and nonnative speech

We investigated native English talkers’ phonetic accommodation to a native or nonnative model talker in a passive auditory exposure setting. We performed a phonetic accommodation experiment, following the procedure of Goldinger & Azuma (2004). Specifically, the imitators read monosyllabic words, disyllabic words, and sentences before and after perceptual exposure to the stimuli. We found evidence of phonetic convergence both to native and nonnative model talkers from various acoustic measurements on words and sentences, and dynamic time warping analyses and XAB perception tests on sentences. We also found that dialect mismatch between participants and native model talkers inhibited phonetic convergence in some acoustic measurements. Additionally, the distances between model talkers and participants along the acoustic measurements before auditory exposure positively affected their degrees of phonetic convergence, regardless of the direction of the change; the farther the acoustic distance was before the auditory exposure, the larger the degree of phonetic convergence was. Moreover, the imitators generalized their accommodation patterns from exposed to unexposed items. Finally, XAB perception tests with the sentences revealed that imitators of all model talkers were perceived as converging towards their model talker, and importantly, this pattern of perceived accommodation was predicted by most of the sentence-based acoustic measurements. We investigated native English talkers’ phonetic accommodation to a native or nonnative model talker in a passive auditory exposure setting. We performed a phonetic accommodation experiment, following the procedure of Goldinger & Azuma (2004). Specifically, the imitators read monosyllabic words, disyllabic words, and sentences before and after perceptual exposure to the stimuli. We found evidence of phonetic convergence both to native and nonnative model talkers from various acoustic measurements on words and sentences, and dynamic time warping analyses and XAB perception tests on sentences. We also found that dialect mismatch between participants and native model talkers inhibited phonetic convergence in some acoustic measurements. Additionally, the distances between model talkers and participants along the acoustic measurements before auditory exposure positively affected their degrees of phonetic convergence, regardless of the direction of the change; the farther the acoustic distance was before the a...

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...

Phonetic convergence after perceptual exposure toward native and nonnative speakers.

This study explores phonetic convergence by native English speakers after perceptual exposure to speech by either a native or a non‐native English speaker. Three native and two Korean non‐native English speakers read two sets of English words and sentences as the model speakers. A separate group of native English speakers read the two material sets, and was then exposed to one of the material sets either through auditory inputs read by a model speaker (experimental groups) or visual inputs (control groups), and read all materials again. Half of the participants were exposed to a native model speaker, and the other half to a non‐native model speaker. Participants also conducted an implicit association test, which measured their attitudes toward native and foreign speakers of English. The first and second recordings of the test talkers were acoustically compared in terms of the Euclidian distances along acoustic‐phonetic dimensions between participants’ postexposure and the model productions, and between th...

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.

Phonetic convergence, communicative efficiency, and language distance

Many English conversations across the globe today involve talkers with different language experiences. Here we show that, while language barriers challenge communicative efficiency, the detrimental effect of language distance may be mitigated by phonetic convergence. We analyzed a corpus of 42 conversations in which talker pairs solved a spot-the-difference puzzle by verbally comparing two scenes only one of which was visible to each talker (“diapix” task). Language distance was varied by pairing talkers who either matched or mismatched in language background and in native/nonnative status relative to the target language. Communicative efficiency was measured by task-completion-time and word type-to-token ratio. Phonetic convergence was assessed by perceptual similarity tests in which listeners (n = 161) compared samples from one talker’s speech to samples from his/her partner’s speech from either early or late portions of the conversation. In this test, greater similarity for late than early samples indi...

Phonetic accommodation in conversations between native and non‐native speakers.

We explored phonetic accommodation during native speaker interactions (four native English pairs and four native Korean pairs) and native–non‐native interactions (four native–non‐native pairs, all speaking English). Speakers engaged in a collaborative picture description task that lasted approximately 20 min. Utterances from relatively early and late in the task were subsequently presented to native English listeners (or Korean listeners, for the Korean‐language dialogues), who were asked to carry out XAB similarity judgments, where X=one talker’s utterance and A/B=early and late utterances from the partner. Phonetic accommodation is indexed by how frequently listeners select the “late” utterance as sounding more similar to the target utterance. An independent group of native English speakers rated the nonnative utterances for degree of accentedness. Phonetic convergence was observed for native‐native conversations (English or Korean), and this was stronger when speakers shared the same or similar dialect...

Word‐level rhythm in non‐native English.

Motivated by traditional rhythm class typologies, studies of language‐learners’ rhythm typically focus on the syllable or segment level. Studying word‐level rhythm lets us explore the effects of lexical features (e.g., part of speech, predictability) on word durations in non‐native speech. This study examined whether native and non‐native English can be distinguished by variation in the realization of English lexical features, and whether non‐native‐like word‐level rhythm leads to a stronger foreign accent. Word durations were measured in English paragraphs read by 12 native American English (AE), 20 native Korean, and 20 native Chinese speakers. AE listeners rated the “accentedness” of these speakers. AE speakers showed greater within‐speaker word duration variance than non‐natives, and non‐native speakers with greater variance received more native‐like accent ratings. Increased AE variance had two causes. AE speakers had shorter relative durations for function words than non‐natives. AE speakers also showed greater variance in their content word durations than non‐natives, perhaps due to differences between words with and without pitch accents. However, both AE and non‐native speakers produced shorter second mentions of words than first mentions, showing sensitivity to lexical predictability. Overall, these findings implicate word‐level rhythm as an important and complex feature of foreign‐accented English.

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...