what is a midland accent? (americans)?

It's in between the northern and southern accents geographically. It's divided further into north midland and south midland. There's really no way for me to explain what it sounds like to someone with a different accent. Either you've heard it, or you haven't.

This is an awesome question, and honestly, I really don't know. I took a course in dialects and the history of the English language, and I've never herad of a "Midland" accent. I assume that the Midland accent has absorbed some of the "Northern" accent (with which I apparently speak), but with much more of the Midwestern mixed in, so it's not as noticeable.

It kind of sounds "flat", for lack of a better term. It's the one British people often try to do but rarelty succeed in. (Apart from people in NYC and the US South, they think all Americans and Canadians sound like that.)