The patch that just started is quite slow and there are many connection problems just getting the launcher to patch at all. What I now encountered is this: I am playing from Germany and on a German Windows installation, but have downloaded and installed the game in English only. Yet the error message on the launcher, when it first tries to connect (before even showing login fields) is displayed in German, not in English.
I suppose at this point it is querying the system language and displaying the string according to that; don’t be that guy, ArenaNet. Automatic language guessing based on the host OS is super-annoying when the user has deliberately chosen a different language.