I recently noticed how people sound when they're talking to foreigners with sketchy English: about the same way spacemen sound when they tell aliens they come in peace.
Over the summer, a few Japanese students stayed over at my mom's house for a few weeks at a time. Just like all students in Japan, they have an English class, and they yearn to understand and speak it well - but how are any of them going to understand if someone speaks like a caveman?
I've seen people try to communicate with them, saying something along the lines of, "Tanaka, we go, mall. Come to eat - food - with us. We go *walking motions with arms* car and drive. You want - come?"
Okay, sure, MAYBE they'd be able to understand that, but who the hell WANTS to? Wouldn't it be slightly more helpful if it were something like "Tanaka, we are going to the mall. We are going to eat. We're going in the car. Do you want to come with us?" It still sounds unnatural, it's not like anyone would really put that much detail into an offer, but spoken smoothly and clearly, I'd be surprised if any English student wouldn't be able to understand it. And unlike the former statement, they'd probably learn some English.
'Course, sooner or later, you'd probably be able to ask them stuff like this the way anyone else would - "wannagoamall?" - but hey, slow down, these people are learning English.