Abstract. Voiceless/p,t,k/are implemented as aspirated stops in English, but as unaspirated stops in l)utch. Wc examined identification of a voice onset time (VOT) continuum ranging from/da/to/ta/in two language "sets" designed to induce native Dutch subjects to perceive the stimuli as if they were listening to Dutch or English. The effect of language set was highly significant, but thc boundary shift was very small (2.1 ms longer in English than in Dutch) for three groups of subjects differing widely in English language proficiency, it nevertheless showed the subjects were aware of acoustic diffcrenccs distinguishing Dutch and English/t/and that the procedures were effective in creating differing language sets. Nearly every subject produced a longer mean VOT in English than Dutch/t/. The magnitude of the production shift was significantly greater for proficient than non-proficient subjects. Proficient Dutch speakers of English produced Dutch/t/with shorter VOT values than non-proficient subjects, suggesting they formed a new category for English/t/. We speculate that the language set effect was small because subjects used their English/t/category to identify stops in both sets. This was probably due to tile fact that the, ynthetic stimuli, which were modeled on the English/t/-/d/contrast, differed substantially from their Dutch/t/category.Zusammenfassung. Stirnmlose/p,t,k/werden im Englischen als aspirierte, im Niederl~.indischen hingegel~ als nicht-aspirierte Explosivlaute klassifiziert. Untersucht wurde die Identifikation eines VOT-Kontinuums beim 0bcrgang wm Ida/nach/ta/ in zwei unterschiedlichen Sprach-"Umgebungen", die nicderliindischen Versuchspcrsonen den Eindruck vcrmittcln solltcn, als h0rten sic die Stimuli in cngllschem oder niederl~indischern Sprachmaterial. Die Umgebung zeigte hochsignifikantc Auswirkungen, doch konnte bei drei Versuchspersonengruppen unterschiedlicher Beherrschung des Englischen nur eine geringe Verschiebung der Beurteilungsgrenze beobachtet werden (VOT 2,1 ms Ifinger im Englischen). Immerhin wurde deutlit.h, dass die Versuchspersonen die akustischen Unterschiede zwischen dem niederl/indischen und englischen /t/ bcmerkten und dass die Prozeduren bei der Bildung unterschiedlicher sprachlicher Umgebungen wirksam waren. Faste jede Versuchsperson produzierte eine Ifingere durchschnittliche VOT fi.ir ein englisches /t/. Dabei war der Betrag der Verschicbung in der Produktion der Fortgeschrittenen deutlich gr('isser. Diese Gruppe artikulierte ein niederi~indisches/t/mit kiirzeren VOT-Werten als dic tibrigen Versuchspcrsonen, was nahelegt, dass sic for das englische/t/eine neue Kategorie bildetc. Wir vermutcn, dass die Wirkung dcr Sprachumgebung gering war, da alle Versuchspersonen ihre cnglische /t/-Katego~ie zur ldentifikation der Expiosivlaute in beiden Umgebungen verwendeten. Dies hing wahrscheinlich mit dem Umstand zusammen, dass die synthetischen Stimuli, die aus dem /t/-/d/-Kontrast des Englischen abgeleitct waren, sich deutlich von ihrer niederlfindischen/t/-Kategorie absetzten.R...

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This study examined imitation of a voice onset time (VOT) continuum ranging from/da/to/ta/by by subjects differing in age and/or linguistic experience. The subjects did not reproduce the incremental increases in VOT linearly, but instead showed abrupt shifts in VOT between two or three VOT response "modes." The location of the response shifts occurred at the same location as phoneme boundaries obtained in a previous identification experiment. This supports the view that the stimuli were categorized before being imitated. Children and adults who spoke just Spanish generally produced only lead and short-lag VOT responses. English monolinguals tended to produce stops with only short-lag and long-lag VOT values. The native Spanish adults and children who spoke English, on the other hand, produced stops with VOT values falling into all three model VOT ranges. This was interpreted to mean that they had established a phonetic category [th] with which to implement the voiceless aspirated realizations of /t/ in English. Their inability to produce English /p,t,k/ with the same values as native speakers of English must therefore be attributed to the information specified in their new English phonetic categories (which might be incorrect as the result of exposure to Spanish-accented English), to partially formed phonetic realization rules, or both.

This study examined production and perception of the contrast between /t/ –/d/ by subjects differing in native language and age. Acoustic analysis revealed that native speakers of English realized word-initial /t/ with significantly longer VOT values (approximately 85 ms) than native speakers of Spanish (approximately 19 ms). Native English and Spanish adults realized /t/ with VOT values that were non-significantly longer than those of 9-year-olds of the same native language background. Native English adults prevoiced /d/ more often than English children, but Spanish adults and children realized /d/ with lead VOT values in nearly every instance. In a labelling task, the native English speakers showed steeper identification functions, and category boundaries at significantly longer VOT values, than age-matched native Spanish subjects. The boundaries of both the native English and Spanish adults occurred at significantly longer VOT values than those of children who spoke the same language. Three possible explanations are offered for the effect of age on stop voicing judgments: the auditory processing of acoustic parameters associated with stops changes with age; listeners require an increasingly long VOT interval to perceive /t/ as they get older because they produce /t/ with somewhat longer VOT values; listeners ‘attune’ their perception to optimally match the stops they hear.