Well..normal is a loaded word, LOL
There is a *chance* the chilkd is just a late talker. This would be a small chance.
The more likely options would be some sort of delay or other problem. The girl might have hearing issues or another medical issue, or it could be something neurological/developmental like an autistic spectrum disorder. It could be a "simple" speech delay that resolves with some therapy.
there is NO reason not to get some early intervention involved. Please urge her to call. Best case scenario, nothing is wrong, LOL!
If *I* were doing a developmental exam on this child, (part of my job), I would have to consider her delayed in language and refer her to EI for therapy. However, the whole picture is very important also - is this child communicating? Using signs, gestures? How are other areas of development? etc.