This paper tests the idea that the speech rate with which surrounding words are spoken affects the mental representation of words and conditions production of words. This possibility is operationalized by measuring a word's ratio of occurrence in speaker-relative fast speech. Other variables shown in the literature to influence speech rate are controlled for in a 10,000-iteration bootstrapping procedure of a mixed-effect linear regression model. The results of the analysis of 39,397 tokens of content words from 1,232 word types in English display a significant effect for a word's ratio of conditioning in speaker-relative fast speech, although the effect size is small or very small. Other variables shown in the literature to condition speech rate also significantly condition speech rate here. This paper suggests that in addition to other aspects of the context of use of words, contextual speech rate also influences the mental representation of words.

We investigate the impact of medium of communication (in-person versus video) on intraspeaker variation in conversation—a process we refer to as medium-shifting. To quantify the effects of medium-shifting and understand its possible motivations, we analyze three variables that show intraspeaker effects of “clear” or “careful” speech: articulation rate, density-controlled vowel space area, and (ING). The data come from matched in-person and video-mediated interviews with thirty-three repeat guests from The Late Show with Stephen Colbert, recorded before and during the COVID-19 pandemic. Mixed-effects regression models show that compared to in-person interviews, video-mediated interviews involve a significantly lower articulation rate and larger vowel space, but no significant difference in (ING). The results suggest that speakers may engage in medium-shifting in order to enhance their intelligibility over video, for example, through more precise articulatory movements and greater contrast between phonemic vowel categories. The null effect of medium on (ING) further suggests that medium-shifting is a motivator of intraspeaker differences even within a single contextual style. An emergent extralinguistic factor affecting speaking behavior and choices, medium-shifting should be carefully considered especially when designing variationist research involving mixed media interviews.

Inspired by information theoretic analyses of L1 speech and language, this study proposes that L1 and L2 speech exhibit distinct information encoding and transmission profiles in the temporal domain. Both the number and average duration of acoustic syllables (i.e., intensity peaks in the temporal envelope) were automatically measured from L1 and L2 recordings of standard texts in English, French, and Spanish. Across languages, L2 acoustic syllables were greater in number (more acoustic syllables/text) and longer in duration (fewer acoustic syllables/second). While substantial syllable reduction (fewer acoustic than orthographic syllables) was evident in both L1 and L2 speech, L2 speech generally exhibited less syllable reduction, resulting in low information density (more syllables with less information/syllable). Low L2 information density compounded low L2 speech rate yielding very low L2 information transmission rate (i.e., less information/second). Overall, this cross-language comparison establishes low information transmission rate as a language-general, distinguishing feature of L2 speech.

Aims: Although IDS is typically described as slower than adult-directed speech (ADS), potential impacts of slower speech on language development have not been examined. We explored whether IDS speech rates in 42 mother–infant dyads at four time periods predicted children's language outcomes at two years. Method: We correlated IDS speech rate with child language outcomes at two years, and contrasted outcomes in dyads displaying high/low rate profiles. Outcomes: Slower IDS rate at 7 months significantly correlated with vocabulary knowledge at two years. Slowed IDS may benefit child language learning even before children first speak.

The study explores the effect of deviations from native speech rhythm and rate norms on the assessement of pronunciation mastery of a second language (L2) when the native language of the learner is either rhythmically similar to or different from the target language. Using the concatenative speech synthesis technique, different versions of the same sentence were created in order to produce segmentally and intonationally identical utterances that differed only in rhythmic patterns and/or speaking rate. Speech rhythm and tempo patterns modeled those from the speech of French or German native learners of English at different proficiency levels. Native British English speakers rated the original sentences and the synthesized utterances for accentedness. The analysis shows that (a) differences in speech rhythm and speaking tempo influence the perception of accentedness; (b) idiosyncratic differences in speech rhythm and speech rate are sufficient to differentiate between the proficiency levels of L2 learners; (c) the relative salience of rhythm and rate on perceived accentedness in L2 speech is modulated by the native language of the learners; and (d) intonation facilitates the perception of finer differences in speech rhythm between otherwise identical utterances. These results emphasize the importance of prosodic timing patterns for the perception of speech delivered by L2 learners.

This paper introduces a novel captioning method, partial and synchronized captioning (PSC), as a tool for developing second language (L2) listening skills. Unlike conventional full captioning, which provides the full text and allows comprehension of the material merely by reading, PSC promotes listening to the speech by presenting a selected subset of words, where each word is synched to its corresponding speech signal. In this method, word-level synchronization is realized by an automatic speech recognition (ASR) system, dedicated to the desired corpora. This feature allows the learners to become familiar with the correspondences between words and their utterances. Partialization is done by automatically selecting words or phrases likely to hinder listening comprehension. In this work we presume that the incidence of infrequent or specific words and fast delivery of speech are major barriers to listening comprehension. The word selection criteria are thus based on three factors: speech rate, word frequency and specificity. The thresholds for these features are adjusted to the proficiency level of the learners. The selected words are presented to aid listening comprehension while the remaining words are masked in order to keep learners listening to the audio. PSC was evaluated against no-captioning and full-captioning conditions using TED videos. The results indicate that PSC leads to the same level of comprehension as the full-captioning method while presenting less than 30% of the transcript. Furthermore, compared with the other methods, PSC can serve as an effective medium for decreasing dependence on captions and preparing learners to listen without any assistance.

This article examines how three factors determine the surface forms of English stop-stop coarticulation across word boundaries in both native and nonnative speech: place of articulation, frequency, and speech rate. The release percentage and closure duration ratio produced by English (L1) and Mandarin (L2) speakers were measured. The results showed that a place order effect was only partially supported in L1 speech but not shown at all in L2 speech. The results also confirmed a gradient lexical effect, finding a significant correlation between self-rated frequency and overlap. In addition, the results showed that increased speech rate did not induce increased overlap, given that speakers from both groups had either more or less overlap at the fast speech rate than at the slow rate.