Presenting on a conference as a Master Student... common or unusual?
I don't have experience as for the linguistics conferences, but from my observations I can tell that while master students' papers are not common, they are not unheard of (especially, but not limited to, as coauthorship with master thesis supervisor). 
There are three remarks that I can make in your situation:


If the conference has double-blind review policy you should be judged based on the merits of your work and your academic status would be irrelevant.
Did you try talking with your supervisor about the paper: maybe she can suggest a coauthorship to increase the acceptance chances? 
Generally my advice would be to submit the abstract: what do you have to lose?


Good luck.