speech problem in child
most commonly is due to hearing problem
if she is having
hearing loss then she will not understand and can't communicate
there may be some syndrome associated with speech impairment which have other features also.
You don't mention about your child's milestones
is her smile, walking, standing were as with her peers
if that was normal then she is having high probability of having hearing problems
however if associated delayed milestones present, she is lost in her world only, and she is having a low iq then associated syndrome has to be assed
please get your child screened for
hearing assessment there are even ways to get it checked even in very small babies.
Don't take it light and consult with
ENT specialist for hearing assessment and if hearing is normal please do see paediatric doctor to rule out any syndromic association