Stability of temporal contrasts across speaking styles in English and Croatian

Abstract

In this paper we investigate the effect of clear speech, a distinct, listener-oriented, intelligibilityenhancing mode of speech production, on vowel and stop consonant contrasts along the temporal dimension in English and Croatian. Our previous work has shown that, in addition to enhancing the overall acoustic salience of the speech signal through a decrease in speaking rate and expansion of pitch range, clear speech modifications increased the spectral distances between vowel categories in both languages despite the different sizes of their vowel inventories (+10 in English, 5 in Croatian). Here, we examine how clear speech affects the duration of English tense ('long') vs. lax ('short') vowels, English vowels preceding voiced ('long') vs. voiceless ('short') coda stops, Croatian long vs. short vowels and Croatian and English VOT duration for voiced and voiceless stops. Overall, the results showed that the proportional distance between the 'short' and 'long' vowel categories and between the voiced and voiceless stop categories was remarkably stable across the two speaking styles in both languages. These results suggest that, in combination with the spectral enhancement of vowel contrasts, language-specific pronunciation norms along the temporal dimension are maintained in clear and conversational speech.

Bidirectional clear speech perception benefit for native and high-proficiency non-native talkers and listeners: Intelligibility and accentedness

“…The acoustic "distance" between the contrastive categories is thus enlarged in clear speech. Importantly, these enhancement strategies were shown to reflect languagespecific phonological and prosodic properties and have been found to vary across languages (Smiljanić and Bradlow, 2008) and even across generations of speakers of the same language in which there is a sound change in progress (Kang and Guion, 2008). Non-native talkers' and listeners' problems in processing their second language (L2) arise, in part, from the lack of extensive experience with the L2 sound structure, including the system of phonological contrasts, language-specific phonetic implementation of those contrasts, phonotactics, and prosody.…”

Acoustic characteristics of clearly spoken English tense and lax vowels

“…For example, Tasko and Greilick (2010) found that although the duration of the diphthong /aI/ and the word in which it was embedded both increased in clear speech, the word-to-vowel ratio remained constant across speaking styles, indicating that speakers rescale word and vowel duration to a similar extent in clear and plain speech. Similarly, Smiljanić and Bradlow (2008) showed that the percentage vowel lengthening in clear speech relative to conversational speech (clearconversational/conversational) also remained stable for tense and lax vowels. These findings suggest relational invariance for vowel duration across speaking styles to maintain the length contrast.…”

“…Previous studies examining English vowels produced in controlled segmental contexts Kewley-Port, 2002, 2007) or excised from natural sentential contexts (Hazan and Baker, 2011;Kim and Davis, 2014;Lam et al, 2012;Lu and Cooke, 2008;Picheny et al, 1986;Smiljanić and Bradlow, 2008) consistently reveal that vowel duration increases in clear speech relative to plain conversational speech. Plain-to-clear vowel modification has also been explored in terms of relative duration to take into account contextual and speaking rate variations.…”

“…Duration is only a secondary cue to the English tense and lax vowel distinction as vowel length contrast is not phonemic in English (Hillenbrand et al, 2000;Reetz and Jongman, 2009;Smiljanić and Bradlow, 2008). However, it still represents an important tensity difference since tense vowels are typically longer than their lax vowel counterparts, presumably resulting from the longer excursions for the articulators to reach the more extreme tense vowel target positions (Hillenbrand et al, 1995;Watson and Harrington, 1999).…”

Intelligibility and Acoustic Characteristics of Clear and Conversational Speech in Telugu (A South Indian Dravidian Language)

“…In the perceptual domain, intelligibility studies established that naturally produced clear speech enhances intelligibility for various listener populations including adults with normal or impaired hearing [7,8,17,19,26,27] elderly adults [23,9] both native and non-native listeners of the target language [2,4,25] and children with and without learning impairments [3].…”