Colin, I don't know if it’s being a "Little Englander" to take language into consideration, or just being practical. I don't know anything about this Brazilian, although the story sounds familiar and if it the same one as I think I read, all quotes were from the players agents, so not surprised he sounds perfect. But that being said, like Williams I'd not disqualify him just because of where he comes from.
But language I'm afraid has to be taken into consideration. Your right we don't need players to rise to the level of the Oxford Debating Society (would any of them?) but a strong command of the language used to communicate on the pitch would be a little more than useful, it would be essential for someone tasked with being a leader.
Who knows what languages the boy speaks, being Brazilian you can assume Portuguese, and most Brazilians can at least get by in Spanish, whether he speaks English or not who knows. But the question is what is the language the leader of the back line will need to speak in order to be effective?
What language would it be best to yell at Pepe in? Spanish I assume, but he has near perfect English also, not sure about his Portuguese. How about Glen, not sure if he speaks either Spanish or Portuguese but sure he speaks English. Jose I'm sure won't mind Spanish, but he speaks very good English. What about Agger or Skrtel (assuming he stays), will the new lad learn Danish or Slovak? Since both speak very good English would that be more likely the best way to communicate? What about marshaling the midfielders to come back to help. Should be fine with Lucas as he's a native Portuguese speaker, but again he has very strong English. What language do we assume the other midfielders are most likely to react to? Well for Stevie, JonJo, Hendo, or Allen I'm thinking English might be best.
This is about being practical, not nationalistic. If I were to employee a sales team I'd want them fluent in the language of the market they would be selling into. They don't have to be native speakers, but the better the language skills the more comfortable I'd be in thinking they could get the job done as selling relies so heavily on communicating; much like being a leader on a football pitch.