In order to keep it simple: català - castellà - anglès un nen = un niño = a kid una nena = una niña = a kid un noi = un chico = a guy una noia = una chica = a girl Sort! :)

Actually, there are many ways of calling boys and girls in all the different Catalan dialects, in Mallorca we say: nin/nina, al·lot/al·lota. In Valencia they say xiquet/xiqueta. In Menorca they say fillet/filleta. And this can go on forever. But this is only so you know there is not just one word for it. You don't need to learn them!! :D