Or assume a default language and then have a clear option to change to something else. That's the same number of clicks in the worst case, but less in the avera

Or assume a default language and then have a clear option to change to something else. That's the same number of clicks in the worst case, but less in the average case. If you use the user agent string in combination with geo-location (and maybe a few other factors such as Facebook API or twitter API heuristics), you could lower the number of wrong languages using a sort of learning algorithm too.