What's the history of the words contigo, conmigo, etc?
They're treated like contractions for con ti and con mi, respectively, but they actually make the word longer rather than shorter, as contractions ought to do.
It occurs to me that there are a whole host of other words in Spanish that have similar spellings and functions (amigo, enemigo, etc) , how do they fit into this puzzle?
Are ti and mi shortened versions of previously used pronouns tigo and migo, or something? This would make the meaning of amigo clear: a- (not) migo (me)