how well does she eat foods, like a variety of textures etc. Apparently being able to eat solid foods is just as important for the mouth muscles as baby talk, when it comes to speach.
Hearing is definetly worth checking.
Go to your health nurse first, 'cause that's free get their opinion on this and other developmental milestones, if they are being reached etc.
then if your still concerned go to your gp.

don't forget kids take 2 different paths, some develope gross motorskills first and are realy active, good at sport, climbers, great hand eye co-ordination etc (kick balls) and other kids develop language and reasoning skills early and absolutley suck at the gross motor skills (otherwise known as my son, who can talk the leg of a horse but hasn't a sporty bone in his body!)