Recent work suggests that speakers’ lexical networks in theirnative and secondary languages are organized somewhatdifferently, with native languages showing greatersystematicity. We here test this claim in a new way, bymaking use of the “Retrieval-induced forgetting” effect(RIF). Specifically, practicing previously encodedinformation through rehearsal is expected to result in bettermemory for that information, regardless of which languagethe information is encoded. The RIF effect involves thesuppression of information that is associated with thepracticed information but is itself unpracticed. Since RIF isunderstood to rely on the association between the practicedand unpracticed memories, we predict it will be weaker whenapplied in a language with weaker or less systematicallyorganized lexical associations. Results confirm that while theexpected practice effect was evident in participants’ nativeand second languages, the RIF effect was only significant inparticipants’ native language. We discuss the relevance andimplications of this finding for second language speakers.