He could very well use any other language, but it seems it is still expected that any European citizen can understand English instead of French or German.
The problem is, what people expected! The most time, i don´t expected everything.
Yesterday, I used the tool first time and my groups were different at all. I never joined in a german group, it doesn´t matter. I had a really good time and my english is worst.
Off topic: So may i can looking for “native english speaker” to explore gw2 and help me to speak english better. I am a german player, so please pm me, like you want.