Agreeing to disagree : constant non-alignment of speech gestures in dialogue

Numerous studies suggest that interlocutors in a dialogue align with each other in terms of their articulatory gestures. It is often suggested that this, first, is the consequence of an automatic tendency for imitation and, second, this fosters mutual understanding. Making use of online archives of media, it was tested whether alignment is hence inevitable. The focus was on the pronunciation of the German word. The standard pronunciation is, but speakers with a Swabian accent produce, acoustically reflected in the fricative spectra. We measured the spectra of fricatives in from interviewers while interviewing either a prominent German politician using the Swabian variant or an interviewee using the standard variant. Results showed neither an overall influence of the interviewees' pronunciation on the fricative realization by the interviewer nor a tendency to align over time for interviewer-interviewee pairs with different pronunciations. This shows that phonetic alignment in conversation is a more complex process than most current theories seem to suggest. Moreover, failure to align may not impede mutual understanding.peer-reviewe

Not all geminates are created equal : evidence from Maltese glottal consonants

Many languages distinguish short and long consonants or singletons and geminates. At a phonetic level, research has established that duration is the main cue to such distinctions but that other, sometimes language-specific, cues contribute to the distinction as well. Different proposals for representing geminates share one assumption: The difference between a singleton and a geminate is relatively uniform for all consonants in a given language. In this paper, Maltese glottal consonants are shown to challenge this view. In production, secondary cues, such as the amount of voicing during closure and the spectral properties of frication noises, are stronger for glottal consonants than for oral ones, and, in perception, the role of secondary cues and duration also varies across consonants. Contrary to the assumption that gemination is a uniform process in a given language, the results show that the relative role of secondary cues and duration may differ across consonants and that gemination may involve language-specific phonetic knowledge that is specific to each consonant. These results question the idea that lexical access in speech processing can be achieved through features.peer-reviewe

On the causes of compensation for coarticulation : evidence for phonological mediation

This study examined whether compensation for coarticulation in fricative-vowel syllables is phonologically mediated or a consequence of auditory processes. Smits (2001a) had shown that compensation occurs for anticipatory lip rounding in a fricative caused by a following rounded vowel in Dutch. In a first experiment, the possibility that compensation is due to general auditory processing was investigated using nonspeech sounds. These did not cause context effects akin to compensation for coarticulation, although nonspeech sounds influenced speech sound identification in an integrative fashion. In a second experiment, a possible phonological basis for compensation for coarticulation was assessed by using audiovisual speech. Visual displays, which induced the perception of a rounded vowel, also influenced compensation for anticipatory lip rounding in the fricative. These results indicate that compensation for anticipatory lip rounding in fricative-vowel syllables is phonologically mediated. This result is discussed in the light of other compensation-for-coarticulation findings and general theories of speech perception.peer-reviewe

The mental lexicon is fully specified : evidence from eye-tracking

Four visual-world experiments, in which listeners heard spoken words and saw printed words, compared an optimal-perception account with the theory of phonological underspecification. This theory argues that default phonological features are not specified in the mental lexicon, leading to asymmetric lexical matching: Mismatching input ("pin") activates lexical entries with underspecified coronal stops ('tin'), but lexical entries with specified labial stops ('pin') are not activated by mismatching input ("tin"). The eye-tracking data failed to show such a pattern. Although words that were phonologically similar to the spoken target attracted more looks than unrelated distractors, this effect was symmetric in Experiment 1 with minimal pairs ("tin"- "pin") and in Experiments 2 and 3 with words with an onset overlap ("peacock" - "teacake"). Experiment 4 revealed that /t/-initial words were looked at more frequently if the spoken input mismatched only in terms of place than if it mismatched in place and voice, contrary to the assumption that /t/ is unspecified for place and voice. These results show that speech perception uses signal-driven information to the fullest, as predicted by an optimal perception account.peer-reviewe

Is vowel normalization independent of lexical processing?

The author wishes to thank James McQueen, Klaus Kohler, Randy Diehl, and an anonymous reviewer for comments on an earlier version of this article and Marloes van der Goot, Laurance Bruggeman, and Jet Sueters for running the experiments.Vowel normalization in speech perception was investigated in three experiments. The range of the second formant in a carrier phrase was manipulated and this affected the perception of a target vowel in a compensatory fashion: A low F2 range in the carrier phrase made it more likely that the target vowel was perceived as a front vowel, that is, with a high F2. Recent experiments indicated that this effect might be moderated by the lexical status of the constituents of the carrier phrase. Manipulation of the lexical status in the present experiments, however, did not affect vowel normalization. In contrast, the range of vowels in the carrier phrase did influence vowel normalization. If the carrier phrase consisted of mid-to-high front vowels only, vowel categories shifted only for mid-to-high front vowels. It is argued that these results are a challenge for episodic models of word recognition.peer-reviewe

The perception of English front vowels by North Holland and Flemish listeners: acoustic similarity predicts and explains cross-linguistic and L2 perception

We investigated whether regional differences in the native language (L1) influence the perception of second language (L2) sounds. Many cross-language and L2 perception studies have assumed that the degree of acoustic similarity between L1 and L2 sounds predicts cross-linguistic and L2 performance. The present study tests this assumption by examining the perception of the English contrast between /e{open}/ and /æ/ in native speakers of Dutch spoken in North Holland (the Netherlands) and in East- and West-Flanders (Belgium). A Linear Discriminant Analysis on acoustic data from both dialects showed that their differences in vowel production, as reported in and Adank, van Hout, and Van de Velde (2007), should influence the perception of the L2 vowels if listeners focus on the vowels' acoustic/auditory properties. Indeed, the results of categorization tasks with Dutch or English vowels as response options showed that the two listener groups differed as predicted by the discriminant analysis. Moreover, the results of the English categorization task revealed that both groups of Dutch listeners displayed the asymmetric pattern found in previous word recognition studies, i.e. English /æ/ was more frequently confused with English /e{open}/ than the reverse. This suggests a strong link between previous L2 word learning results and the present L2 perceptual assimilation patterns

How phonological reductions sometimes help the listener

In speech production, high-frequency words are more likely than low-frequency words to be phonologically reduced. We tested in an eye-tracking experiment whether listeners can make use of this correlation between lexical frequency and phonological realization of words. Participants heard prefixed verbs in which the prefix was either fully produced or reduced. Simultaneously, they saw a high-frequency verb and a low-frequency verb with this prefix—plus 2 distractors—on a computer screen. Participants were more likely to look at the high-frequency verb when they heard a reduced prefix than when they heard a fully produced prefix. Listeners hence exploit the correlation of lexical frequency and phonological reduction and assume that a reduced prefix is more likely to belong to a high-frequency word. This shows that reductions do not necessarily burden the listener but may in fact have a communicative function, in line with functional theories of phonology.peer-reviewe

Correlation versus causation in multisensory perception

This research was supported in part by an Innovational Research Incentive Scheme Veni Grant awarded to A.J. by the Netherlands Organization for Scientific Research (NWO). The authors thank Sabrina Jung for help with the preparation of the materials and Lies Cuijpers for help with conducting the experiments.Events are often perceived in multiple modalities. The co-occurring proximal visual and auditory stimuli events are mostly also causally linked to the distal event, which makes it difficult to evaluate whether learned correlation or perceived causation guides binding in multisensory perception. Piano tones are an interesting exception: They are associated with the act of the pianist striking keys, an event that is visible to the perceiver, but directly results from hammers hitting strings, an event that typically is not visible to the perceiver. We examined the influence of seeing the hammer or the keystroke on auditory temporal order judgments (TOJs). Participants judged the temporal order of a dog bark and a piano tone, while seeing the piano stroke shifted temporally relative to its audio signal. Visual lead increased “piano-first” responses in auditory TOJ, but more so if the associated keystroke was visible than if the sound-producing hammer was visible, even though both were equally visually salient. This provides evidence for a learning account of audiovisual perception.peer-reviewe

Coping with phonological assimilation in speech perception : evidence for early compensation

The pronunciation of the same word may vary considerably as a consequence of its context. The Dutch word tuin (English, garden) may be pronounced tuim if followed by bank (English, bench), but not if followed by stoel (English, chair). In a series of four experiments, we examined how Dutch listeners cope with this context sensitivity in their native language. A first word identification experiment showed that the perception of a word-final nasal depends on the subsequent context. Viable assimilations, but not unviable assimilations, were often confused perceptually with canonical word forms in a word identification task. Two control experiments ruled out the possibility that this effect was caused by perceptual masking or was influenced by lexical top-down effects. A passive-listening study in which electrophysiological measurements were used showed that only unviable, but not viable, phonological changes elicited a significant mismatch negativity. The results indicate that phonological assimilations are dealt with by an early prelexical mechanism.peer-reviewe

Top-down effects on compensation for coarticulation are not replicable

Listeners use lexical knowledge to judge what speech sounds they heard. I investigated whether such lexical influences are truly top-down or just reflect a merging of perceptual and lexical constraints. This is achieved by testing whether the lexically determined identity of a phone exerts the appropriate context effects on surrounding phones. The current investigations focuses on compensation for coarticulation in vowel-fricative sequences, where the presence of a rounded vowel (/y/ rather than /i/) leads fricatives to be perceived as /s/ rather than /∫/. This results was consistently found in all three experiments. A vowel was also more likely to be perceived as rounded /y/ if that lead listeners to be perceive words rather than nonwords (Dutch: meny, English id. vs. meni nonword). This lexical influence on the perception of the vowel had, however, no consistent influence on the perception of following fricative.peer-reviewe