F14Smith,
I don't think you will have any trouple if you answer PSA in your own language. Because if they have thought that it would be a problem, they wouldn't give you the option. If you are willing to fill it in your own language just to be more comfortable then it is OK. However if you are doing that because you don't trust your language level, i would strongly recommend you to reconsider applying for Qatar. Because they are going to be looking for a certain level of english language.