This is a longitudinal case study of two Farsi-speaking children learning English: ‘Bernard’ and ‘Melissa’, who were 7;4 and 8;4 at the start of data collection. The research deals with the presence or absence of functional categories (CP),in our case Yes/no questions, Wh-questions, and embedded clauses as well as their production rate in early stages of interlanguage development of the child second language (L2) acquisition of syntax. Some studies in the field of child second language acquisition regarding the production of functional categories (CP) are discussed. Examining data collected from the children’s spontaneous speech, the researcher’s diaries and translation and other tasks over a period of 20 months, the competing claims of the two most prominent hypotheses about early L2 grammars are tested: Vainikka& Young-Scholten’s (1996) Minimal Trees/Structure Building hypothesis and Schwartz & Sprouse’s (1996). Full Transfer/Full Access hypothesis. The conclusion is reached that Yes/no questions, Wh-questions, and embedded clauses as three functional categories are absent in early stages of interlanguage development of the child L2acquisition.Keywords: Functional categories, Child L2 acquisition, Minimal Trees/Structure Building hypothesis, Full transfer/fullaccess hypothesis, Yes/no questions and Wh-questions, Embedded clauses