Yeah, that could be an interesting use of LLMs. It could at least tell you which languages might be present in the input text.

In the 1980s, we had a version of 7-bit ASCII in Sweden where the three extra Swedish vowels "åäö" were represented by "{}|".

So what might look like regular US 7-bit ASCII should be interpreted as the Swedish version if the text is in Swedish with "{}|" where "åäö" normally goes.