First, off, as a script read, it's actually quite fun to do so. My sister and I enjoyed being able to play the characters roles, however the main issue with this is the fact we were unaware of what roles we were actually playing. There was very little detail as to the characterization of the characters. We were left to assume how each character spoke and what was their natural locale.
Another glaring issue for us was the fact that we were not exactly following the story-line. It was a cold open, which in itself isn't a bad thing. However, you want you audience to be aware at the very beginning of where the story is and where it will lead too. I was aware that Tammy was fresh from a break-up because of the log line. However you need to express this in the screenplay's story progression. The audience will not follow without the context.
However, I will say, that assuming that the characters live in a southern state or least a state with the southern mentality, it was natural for I and my sister to read the dialogue. We both live in a southern state. So I felt that the dialogue was actually natural and comedic in tone, which is what you were going for.
Still, the script is riddled with cliches, something that is okay from time to time, as cliches are a callback to something before that most people fondly remember. However, you do not want to overstate a cliche to often. It can take away from the originality of your screenplay, and it can be a crutch.
Overall, I have to say, that this screenplay does need work. In fact, I believe that it would be better suited to be written as a book rather than a screenplay. If you ever get a chance to, check out my screenplays Androids #1 & Project Zero #1. You might like what you read or hate it! And that's fine! We're all here to help each other improve, so let's do it!