&24/ Hands-on: Language Selection, not Country Selection

No, please don't go for it. As stated above: Flags symbolize countries, not languages.

The W3C says:

Best Practice 16: Using flags to indicate languages

Do not use flag icons to indicate languages.
No UA applicability issues.
How to: Use text. See Example 23 for one illustration.
Discussion: Flags represent countries, not languages. Numerous countries use the same language as another country, and numerous countries have more than one official language. Flags don't map onto these permutations.

Jakob Nielsen says:

The problem with using flags as symbols for language choice is that some languages are spoken in many countries. For example, using an American flag for the English language understandably makes the British upset (they invented the thing, after all) and also irritates Canadians and many others. Of course, using a Canadian flag wouldn't work since many Canadians speak French. The recommended solution is to use flags that match the geographical location of the service and its main intended audience. For example, a tourist site in Continental Europe would use a British flag for English unless it was mostly targeted at American tourists, whereas a tourist site in the Americas would use a U.S. flag unless it was mostly targeted at Europeans. I have seen the English flag used once, but would generally recommend against this seemingly neutral choice since few people outside the U.K. know the regional flags for England, Scotland, etc.