In Google Docs, I imported a Word document and converted it to a Google doc. The spell checker didn't recognize English words such as "Monday" and "February". I assume that the document isn't using English for the spell checker language.
How can this setting be changed in a Google Document?
It wasn't using local language settings. Maybe because it started life as a Word doc (speculation). If I go into the setting and change it to Francais (French), spell check complains about "Monday". Change it back back to English, spell check doesn't complain about "Monday". So the Language setting affects spell check.