We compared 2 learning methods for the acquisition of vocabulary in a second language (L2). In addition, the use of the new L2 words was evaluated both in isolation and within sentences. In the semantic method, L2 words and pictures denoting their meanings were presented and participants learned by practicing a semantic categorization task (to indicate whether new words were exemplars of semantic categories). In the lexical methods, individuals received L1-L2 word pairs and they performed a letter-monitoring task (to indicate whether L1-L2 words contained a grapheme). After training, compared with the lexical learning group, the semantic learning group showed: (a) no cost between training sessions, (b) better performance in out-of-context tasks (e.g., picture naming), and (c) an efficient processing of L2 words in sentences. The pattern of outcomes shows the advantage of semantic learning for the acquisition and the use of L2 words in isolation and within sentences.