This study investigated the effects of perceptual and production training on the abilities of adult native speakers of Spanish to identify and produce the English vowels /i, I, e, ε, æ/. Testing was performed prior to and following an average of 12 h of perceptual training in a category inclusion task, then again following an average of 7.5 h of production training involving visual feedback of vowel formant (F1 and F2) values. A lagged control group of participants who were delayed in starting training showed no improvement in perception and production skills during the control period but changed equivalently during training. The mean improvement in perceptual identification accuracy for /i, I, e, ε/ was 17%. The mean improvement in the intelligibility of participants productions of /I, ε, æ/ following training was 11%. For both perception and production, most improvement occurred during perceptual training.