Currently Being ModeratedSep 7, 2013 10:27 AM (in response to videoz)
The definitions dictionary has nothing to do with spell check. You can't edit the New Oxford Dictionary dictionary, and it wouldn't have any effect on spell check even if you could. (In fact, the "definition" of teh that you are seeing is from Wikipedia, not from a dictionary at all.)
It sounds like spell check might not be working in Mail. Is it turned on in Mail?
Currently Being ModeratedFeb 8, 2014 8:06 PM (in response to videoz)
I have the same problem and it is definitely affecting spell check. As 'teh' is now recognised as a work the sub menu no longer suggests the correct spelling and I have to go through the text (email and otherwise) to spot them manually myslef. Quite ridiculous that typos are inlcuded