Bad words

How do you implement not saying bad words around your child if people around her do and directly to her. It’s common in Spanish to use words like the f word ex: where’s your effing dad “pinche” is what is common and it irritates my that people find it ok with my 6 month old ... my biggest issue is that my MIL is the one who usually says it and my partner is right behind her.. it’s so naturally for them they don’t see anything wrong with it until I make a gesture but by then they’ve already said it..