7. The method as in claim 6 , wherein receiving the feedback includes: analyzing the out-of-vocabulary word via a secondary text-to-speech synthesizer that attempts to convert the out-of-vocabulary in a foreign language with respect to the first language; and producing the feedback in response to detecting that the out-of-vocabulary word is present in a lexicon lookup used by the secondary text-to-speech synthesizer to convert text into speech.
6. The method as in claim 1 , wherein detecting the likelihood that the out-of-vocabulary word will be mispronounced using the primary text-to-speech synthesizer includes: implementing the primary text-to-speech synthesizer in a first language, the out-of-vocabulary word being absent from a lexicon lookup of the first language.