Here is common to write "mejicano" instead of "mexicano". I've learnt to write "mexicano" here, in the forums (although I knew this word, of course). Also Texas is written Tejas (I pronounce "teksas" for Texas and "tejas" for Tejas).
I didn't know the third meaning. It's good to know. Thanks.
Edit: Is it correct to say "nahua" instead of "náhuatl"?