I talk to them in Spanish and they don't seem foreigners at all, but you'd need to believe I'm Spanish too and therefore able to spot the differences. About other circumstancial proofs, Celestina is the name of a famous old matchmaker in Spanish literature from a classic book from the 15th century titled, well, 'La Celestina' (in fact, 'celestina' has become the common noun in Spanish for matchmakers); also, her deceased husband in the game was named Calisto, which is the name of the main protagonist of that book.