When you work in multi language environment the squiggles are often less than useful. They are just visual noise I must fight or ignore because the system tries to guess the language of the text I'm writing and it is most often wrong. And manually switching language settings between each interaction is way to inconvenient.

I used character styles that set the proofing language with hot keys assigned, so shift-alt-1 sets to English, shift-alt-2 to German, etc. As character styles they apply both to the current insertion point when typing or any selected range (e.g. when I forgot to set it proactively and now have a line spattered with wiggles)

Or just set the proofing language for the entire text to None to banish all spelling and grammar diagnostics.