Opinions are divided, otherwise I wouldn't be asking...

On one side we have the fact that without adding VOIP and probably some significant classroom time people don't really get to grips with using the language in any formal sense. One group of international architects are working together in English in SL quite deliberately, but their time in SL is only about 10% of their English learning time for example.

However, most of us don't need such technical language, we are more interested in conversation whilst on holiday or similar. We're less bothered about the correct form of the future perfect, more in ordering a coffee and some food, and asking for directions. Second Life can provide that in spades, even without VOIP. You can, without pestering them, find people from many nations on earth within SL and if you become friends start to learn how to say hello, what's for lunch, where's the good clothes shops etc. - the sorts of things you actually want on your holiday.

Do you actually live close to a Japanese speaker, and an English speaker and a Portuguese speaker and a French Speaker and a German speaker, and a Korean speaker and a Russian speaker and a Chinese speaker and... well that's the mix of languages I can think of from people on my friends list in SL. These aren't people that studied it at school and on their holidays, these are native speakers of those languages, sat in their culture. I've learnt billets-doux that are current and idiomatic ways to order glasses of water in Portuguese if I'm in Lisbon, glasses with water elsewhere!

Forget your phrase book with "In the street", "At the doctors", "At the hotel" Second Life may not get you the qualification in a foreign language for a job, well not yet anyway, but don't you think you can learn your enough to feel a bit more confident on your holiday by chatting to your friends? Just like you'll be chatting when you're actually there!