I'm not sure if this should be a feature request, or a bug report. Basically, I spend a lot of time working on multi lingual documents in English and a Southeast Asian language such as Thai, Khmer, or Myanmar. I'm a very poor speller, so I appreciate the spell checker on the English text. However, it is annoying that the Asian text is always marked as misspelled.
In the case where there is some kind of mark underneath the Asian consonants the red misspelled underlining makes it difficult to even read the text.
All the languages that I am concerned about encode their characters in a different Unicode block than English. It seems like it should be relatively simple for the English spell-checker to only check words that use characters within the Latin code block.
Providing spell checks for the other languages would be nice too, but by no means essential. Just get rid of the red underlining.