Typing in Terminal underlines characters - adds accented characters

Whenever I type in Terminal now (it never happened before, I must've enabled it by accident), I get an option to enter an accented character. I want to turn this off.

It looks like this:

$ git a_d_ (imagine d is underlined, i can't underline in StackExchange apparently) 

Then when I type d again, it makes it:

$ git ađ

This is really annoying behavior. How do I turn off this autocomplete thing?