Rather ironically, the OP on this question misspelled [tag:spelling] so we now have a tag called [tag:spelign].

http://apple.stackexchange.com/questions/269923/verify-the-automatic-language-detection

How are these dealt with?  

I didn't just want to retag it [tag:spelling] or [tag:spell-check] as I'm not sure what that would then do with the orphaned tag.