Apples spellchecking has lately become really bad when it comes to Swedish, and the ability to use Swedish+English at the same time is even worse (I had to disable it). The biggest problem is that in Swedish we string words together, for example “göralös” (=have nothing to do) which according to Apple should be “göra lös” (=do lose 🤷🏻). These spaces can be really important, one fun example (that apples spellchecking handles) is “långhårig sjuksköterska” (nurse with long hair) which divided into words would become “lång hårig sjuk sköterska” (tall, hairy, sick nurse).
Anyway, the spell checking is starting to become so bad that I seriously considering turning it off for Swedish.