I think language might be piggybacking off cultural norms and expectations as well. For example (generalization incoming) in Portugal the farther north you go,

I think language might be piggybacking off cultural norms and expectations as well. For example (generalization incoming) in Portugal the farther north you go, the looser tongues get. People from Lisbon (central Portugal) and down south are far more proper and don't curse as much.