The present study explored the production and perception of the /i/-/I/ vowel contrast in second language (L2)-dominant early learners of American English who no longer fluently speak their first language (L1, Spanish). The production task analyzed the extent to which the early learner group differed from controls (native English speakers and L1-Spanish late-onset learners of English) with regard to duration and spectral centroids. The perception experiment examined how these early learners classified resynthesized stimuli drawn from the /i/-/I/ contrast using distinct acoustic cues - spectral and temporal - in a 2-alternative forced choice identification task. The first experiment revealed that the early learners produced the contrast in a native-like manner in terms of the spectral envelope and duration use. The second experiment found that early learners differed from both control groups in how they categorized the /i/-/I/ continua based on spectrum and duration, and the extent to which they rely on these two cues. The effects of linguistic experience on L2 phonetic behavior are discussed.