Despite the prevalence of bilingualism, language acquisition research has focused on monolingual infants. Monolinguals cannot learn minimally different words (e.g., "bih" and "dih") in a laboratory task until 17 months of age (J. F. Werker, C. T. Fennell, K. M. Corcoran, & C. L. Stager, 2002). This study was extended to 14- to 20-month-old bilingual infants: a heterogeneous sample (English and another language; N = 48) and two homogeneous samples (28 English-Chinese and 25 English-French infants). In all samples, bilinguals did not learn similar-sounding words until 20 months, indicating that they use relevant language sounds (i.e., consonants) to direct word learning developmentally later than monolinguals, possibly due to the increased cognitive load of learning two languages. However, this developmental pattern may be adaptive for bilingual word learning.