The purpose of this research is investigation into the difference of linguistic-cognitive skills in bi-lingual
students, who have difference economical-social backgrounds. Two viewpoints have been in mind while
conducting this research: First, Vigotsky's theory about general cognitive development, which is applicable in
learning language. Second, Bernstein's theory of social class and the differences of speech quality. In this
research suitable theoretical explanations being suggested so that the various effects of cognitive behaviors are
clarified in learning the second language. Moreover, learning of the second language is being discussed in its
social framework. The subjects of this research include 205 grade one students of public schools in the city of
Orumieh. The age of these kids is between six and a half years to eight and a half years. These kids native language
is either Turkish or Kurdish and are taught their lessons in Farsi language. They are selected from various social
and economical levels. 
The test for ability in Farsi language (the test for ability in writing words) is used for the bi-lingual kids.
The results of this research shows clear signs that social class is in relationship with the linguistic-cognitive
development and states that the kids' primary experiences in family and social group channels can impact the
structure of their cognitive and linguistic development. At the meantime, the research findings did not provide any
clear sign with regards to the relationship between culture and linguistic-cognitive development, meaning
that although there is cultural differences between Kurdish-speaking and Turkish-speaking kids in the
region, the level of gaining Farsi knowledge of the two groups has had no significant statistical difference. The
most important outcome of this research stresses the question that the amount of educational resource at hand
can to what extent impact the education development in the second language for bi-lingual kids. Kids who have
had the opportunity to pass pre-primary school classes have had far more ability in learning Farsi knowledge
compared to