Not laughing at the person, laughing at the confusion. I try to find the humor in things, helps me to smile more which leads to a more positive attitude and a positive attitude is a good things to have.
I try to understand what the person means, regardless of how they say it. When I think I understand, I try to rephrase it and see if that's what was meant, to be sure. That way if someone else is having a problem understanding, when they get to my post and see that's what they meant, it will help to get the idea across better. Likewise, if someone else figures it out and restates it, it helps me to understand what the person meant.
As a point that I sometimes make to people (this works best for those who understand English and it's structure):
Tha perpus ov werdz iz to commoonekayt a thawt. (The purpose of words is to communicate a thought.)
In other words, it doesn't matter how someone spells it or says it, so long as the idea makes it way across, the goal is accomplished. So I don't go saying "You said it wrong so you must be stupid" or anything like that. At times, I may give the person some guidance on how it's said or what to say, but I never judge a person for trying. :)