The baby's first words producing is one of the most important index of development. Development of talking is through a complex process that is influenced by both neuromaturation and human relationships (environment). It is not an imitative function in which children learn to repeat what they hear, but also it is a creative process through which children master a rule based, symbolic system. Talking development can be evaluated in 5 important dimensions: phonology, semantics, morphology, syntax and pragmatic. The receptive and expressive abilities of the child must be evaluated also. This paper discusses about the epidemiology, etiology and pathogenesis, clinical manifestations, how to assessment and make early diagnosis, differential diagnosis, management (treatment and rehabilitation) and prognosis of delayed or atypical talking in addition to above definitions. This paper also emphasizes on early intervention for children who develop significant behavior problems secondary to their communication difficulties and for whom long-term problems in social development are a major concern.

A 4 years old blind boy with leber's congenital amaurosis was referred for his severe expressive language problems. There was a considerable discrepancy between receptive and expressive language capabilities in favor of receptive ones. Behavioral problems such as temper tantrums, object dependency and cliche form movements, caused a referral to psychiatrist, which led to a short term drug prescription. Since it was revealed that he was able to perceive and reproduce rhythms presented to him, this capability was used for his speech training. This method of training have been appeared to be successful. His behavioral problems are controlled, he began to communicate vernally and his intellectual functioning is much better than prior to the therapy.

Objective: Considering the fact that children with Down Syndrome have a severe delay in language development which does not appear being improved by language therapy leaning on auditory modality, this research was aimed to compare the traditional educational method and reading method effects on receptive and expressive language of 4 – 10 years old Down Syndrome children with 40 – 60 I.Q scores.

Materials & Methods: In this quasi experimental and interventional research from Navide Asr Rehabilitation clinic in Tehran, Rezvan Rehabilitation clinic in Shahriar, Ehsan Rehabilitation clinic in Karaj and Down Syndrome Association of Karaj, 20 Down Syndrome children were selected by simple and convenient sampling from 96 Down Syndrome children and were allocated into two groups by balanced randomized method. The first group was educated by whole word reading method and the other group was educated by traditional method. Both groups had three 15-minute educational sessions per week for a period of 6-month. Languages of both groups have been examined by TOLD- P: 3 test as pre and post-test. The results were analyzed by statistical tests including Kolmogoroff - Smironoff (K-S), Independent-T-Test and Paired-T-Test.

Results: Independent-T-Test in both groups revealed no significant differences before education in receptive (P=0.452), expressive (P=0.1) and speech (P=0.428) Language, but after intervention period, the groups have significant statistical differences in all language portions such as receptive (P=0.043), expressive (P<0.001) and Speech (P<0.001).

Conclusion: Reading education has more effects on receptive and expressive language in children with Down syndrome than the other educational methods (traditional ones). Thus it seems that focusing on behavioral and cognitive phenotype of Down syndrome with emphasis on visual modality facilitates language development more than auditory modality, and aptitude training may have the best effects.