This study investigated interactions among linguistics, social and political factors in a linguistically rich environment. For this purpose, two-hundred Iranian preschoolers (aged 5 to 6 years old) from four ethnic/linguistic groups (Arab, Kurd, Turk and Fars) were selected using multi-stage stratified sampling. All participants took part in an Elementary English language course and their exposure to foreground TV was recorded using media exposure portfolio. Maternal education and family income were considered as criteria for socio-economic status. Children's language proficiency was measured through Language Sample Analysis (LSA). The LSA components included total number of utterances produced, total number of words produced, total number of new words produced and mean length of utterances. Regression analysis, ANOVA and t-tests were used for data analyses. The results showed that bilingual children performed slightly better than multilingual children in LSA measures but this cannot be taken for granted. Moreover, socio-economic status and LSA measures were significantly related but TV exposure was not associated with the LSA measures. These results supported the arguments purported by minority language proponents on the importance of using children's mother tongue in educational curriculum. •Multilingualism is becoming the norm in educational and social spheres.•Multilingualism is associated with political, social and educational consequences.•Differences between bilingual and multilingual children are less investigated.•Exposure to TV, socioeconomic status and mother tongue literacy are important predictors of multilingualism.•Multilingual children are not falling behind their bilingual counterparts regarding language measures.