1. A non-transitory processor-readable medium storing code representing instructions to be executed by a processor, the code comprising code to cause the processor to: receive acoustic data representing an utterance spoken by a language learner in a non-native language in response to prompting the language learner to recite a word in the non-native language; receive a pronunciation lexicon of the word in the non-native language, the pronunciation lexicon of the word including at least one alternative pronunciation of the word determined based on a pronunciation lexicon of a native language of the language learner; generate an acoustic model of the at least one alternative pronunciation of the word from the pronunciation lexicon of the word in the non-native language; identify a mispronunciation of the word in the utterance based on a comparison of the acoustic data with the acoustic model; and send feedback related to the mispronunciation of the word to the language learner.