How's their Spanish?
Roberts is pretty much the best. I notice we've not rushed to hire Chelsea's old one so there's at least one big six club he trumps.
Their Spanish might be as limited as the relevance of them knowing Spanish or not. You may struggle with it, but others are capable of being friends and mentors without knowing any Spanish.
If you say Roberts is the best then maybe thats the case. Personally I haven't watched too many English GK coaches during training sessions.