Harnessing time: Leveraging chronotype asynchrony to promote efficient speech learning

This study examined chronotype synchrony effects on learning a nonnative speech contrast. Fifty-nine young adult native speakers of American English completed a circadian preference questionnaire and trained on producing a Danish vowel contrast in the morning or evening. Perceptual change (discrimination and identification, n = 26) and production change (acoustic distance from a native model, n = 59) were assessed. Identification improved with training, but improvement did not depend on circadian preference or training time. Production gains were greater when training occurred outside learners' preferred time, although the effect was small, suggesting that speech-motor learning may benefit from reduced executive control.