An evaluation is suggested. Begin with your pediatrician.

It is very difficult to say what causes a speech impediment. It could be several things such as: dentition, a motor planning difficulty, "bad habits" (for some reason learned to say a sound the wrong way), overall development, etc. Many children experience a period of time when they can not say 1 or more sounds in their development. Acquisition of speech sounds begins at 3 and goes all the way to 9 years of age.

Without knowing the specifics it’s hard to say. In general, children, just like flowers, bloom on their own time and through speech therapy she should find some improvement. I would seek out a speech and language evaluation.

Ali Matisse, MS CCC-SLP