Are there specific 'Kerala-variant' phrases I should avoid in Trivandrum?

I'm planning a trip to Kerala next month and I'm really nervous about my accent. I've heard that the Malayalam spoken in the north (Malabar) is quite different from what you hear in the south. If I use standardized or 'TV' Malayalam, will locals in Trivandrum think I sound weird? I want to make sure I don't come off as rude; are there any regional trap-words I should steer clear of?