User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7) Gecko/20040616 Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7) Gecko/20040616 Spell checking features in thunderbird works when message is not written in English. It should check a MIME-character encoding field in header. Reproducible: Always Steps to Reproduce: 1. Spell check for a message (like Japanese or Korian) 2. 3. Actual Results: Thunderbird tries to check spelling and generate odd results. Expected Results: Skips spell checking. It doesn't occur on 0.7. I think this bug is introduced 0.7.1.

I don't think checking MIME-character encoding is a good idea to take decisions on spelling. I personally use ISO-8859 encoding to write messages in english, french and spanish . Ans MIME-encoding happens _after_ the message has been composed, doesn't it ? Perhaps this should be a ENH request for a default language preference of message composition, with various languages fallbacks (like the languages preference for the FireFox browser), with a button to choose alternate languages on a per-message basis ?

*** This bug has been marked as a duplicate of 69687 ***