This study evaluated the efficacy of the computer-assisted intervention program known as Fast ForWord Language? in a sample of migrant students in Grades 1 through 6 who were native Spanish speakers. Fast ForWord Language? combines intensive training in multiple receptive English language skills with adaptive acoustic waveform lengthening and amplification to purportedly accelerate the English language learning skills of children who are nonnative English language speakers. Students either were randomly assigned to a treatment or no-contact control condition or were matched on grade, English language proficiency, and nonverbal IQ. All students were assessed in five domains before and immediately after the 4- to 8-week intervention: (a) spoken English language proficiency; (b) oral language competency; (c) phonological awareness; (d) basic reading skills; and (e) classroom behavior. Except for performance on a measure of sight-word recognition, on which children in the treatment group achieved a significantly greater gain than those in the control group, changes in test scores from pretest to posttest were equivalent for the two groups. However, when students who were least fluent in spoken English in each group were compared, the children in the treatment group demonstrated superior gains in expressive language, sight-word recognition, and pseudoword decoding. Thus, Fast ForWord Language? had a substantial, albeit limited impact on the oral language skills and reading performance of migrant children in this study. However, due to methodological weaknesses and limited treatment fidelity, the study results must be interpreted cautiously.