Ha, can sympathise with the parent speaking Spanish thing, my dad does it, but the funny thing is to watch my cousins. They will go from Spanish to English and not even realise it. My dad refuses to speak Spanish to me because then I get confused, and reply in French. The following is the only conversation we've had:
Me: Yo tengo una regla.
Him: Si?
Me: Si. And however you say it is purple and bendy, that's what it is.
Him: (It is purple and bendy in Spanish)
Me: That one.
Him: How big is it? (He's given up on me.)
Me: Treinta.... centimetres (done in a French accent.)
I go from French to Spanish, with my counting.... I was sitting there with my Tata counting and he was going, "No, mi vida, quince, not quinze."
Pretty easy the course, although I'm behind... I should get it all done though, here's hoping.