Some multiple-language selectors do not need to be complicated. My own Family Portal website can be an example for that. I have just 3 language versions for members of family living in Canada, USA, Poland and Germany.
In this case, I use a simple language selector in the corner of the navbar. Three flags accompanied by words describing respective language (in native form – for an obvious reason).
But big multi-national companies and commerce sites need a lot more specific selectors – not only for language, but also for geographical regions, currencies, units of measure, shipping locations, etc. This can get very complicated.
If any of you are building sites of that kind, you might be interested to know how others are dealing with this issue. I have just read a quite interesting article in Smashing Magazine: