https://en.wikipedia.org/wiki/A_language_is_a_dialect_with_a... but it seems that in the US, even dialects need to be armed to stand their ground.

Here in Norway, we just call any regional language difference dialectal (unless of course you get to call it a different language, cf. above link). That takes away the need to argue about how much linguistic difference is needed for two dialects to be considered separate or why the difference occurred or whether it's "correct grammar" – if people speak their language differently because they're from different places, that's a dialectal difference. (Anyone who speaks a language thus speaks a dialect of that language.) Simple, but rigorous. There's no value judgement, it's just a factual description.