I speak five languages fairly fluently (and English is my 5th one), therefore I believe I can offer you a sound advice. I learned the languages the old-fashioned way - by speaking. For example, my wife is an American, thus English was her first language. I was 22 when we started dating and could not put two words together, but as we continued to communicate my knowledge of English and ability to speak it increased... One observation though: your friend CANNOT be too shy to make mistakes, otherwise he/she will never learn... Also, your friend should not be too shy to be corrected when he/she does make a mistake.
Of course, I've hear of Rosetta Stone's Cd's. I do not know anything about them to feel confident enough to recommend them... My advice is to practice, practice, and practice...
Hope it helps.
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