Create a role?

Other than asking her to do a reading or including her in your wedding party, there aren't really any other ways to give someone a role that wouldn't be just asking them to do some work. If you are ordering corsages for some people, get one for her, too. And also add her to the picture list with your photographer.

This is just me because I don't like public speeches even if it's just a ready. I would rather just be a guest if I wasn't in the bridal party.

You can still invite your friend to the shower/bachelorette if you are having those. I have also seen friends get asked to be their something blue and still get to do all the things a bridesmaid does except stand (ie. they walk down the aisle and then sit down but still treated as a bridesmaid as far as being in the wedding party).