Child speech disability

Dear all,
4 and half years old girl does not speak. she has a twin brother but he has no developmental problems.
Medical History:
Prenatal history is reportedly normal.Perinetal history reports caesarean delivery.
Cytogenetics laboratory reported female chromosome complement observed. No abnormality detected.
CT scan of the brain does not show appreciable intra-cranian abnormality. The assymetric cranium, suggests plagiocephaly.
Developmental history:
All developmental milestones were delayed compared to the normal development of her brother. she walked at 1.6 years. the speech is very delayed in terms of saying the word [baj] at the age of 3.6 years.
She pays attention to what is said to her but not more thatn 2 minutes.
She started to follow simple directions only 2 months ago.
She can't express herself verbally.
Newly she started trying to play with her friends. Before she used to get discouraged.
Above medical info is from a local MedCenter.

We appreciate any advise!

Thanks
Riad

[Kevin Kennedy, Ph.D.]

I'm assuming that the plagiocephaly is positional in nature and not the result of fusion of cranial suture, since you're not mentioning surgical correction of the condition. The developmental delays across the spectrum of motor, speech/language and social behavior represent a developmental disorder, but the nature of this should be determined and may well include cognitive deficits. The immediate relevance pertains to the need for specialized pre-school services. Has a pre-school cognitive battery been completed; if so, what were the findings?