You should be able to put just "Puhumme vain.."
Well... There is no error if you do that, at least not today. Perhaps you reported it and it was fixed. I don't think you need to make comments when reporting this kind of errors, just check the right box in the "report box".
Why not "englantiaa"?
It's because the base word is englanti (not englantia). So you have already added the -a in englantia.