_1687064565 20230618050245000 Rovedar Daryoushbabazadeh@gmail.com Rovedar Journal of Contemporary Language Research J. Contemp. Lang. Res. 2980-8065 09 25 2022 1 1 Farnaz Farrokh Alaee https://orcid.org/0000-0001-8860-9993 Introduction: The innateness of language faculty and universal constraints, especially its independency from other mental disciplines, is a robust theory yet under investigation. This study is another contribution to making decisions on competence through performance. Methodology: The project applied an expressive grammaticality judgment task on principles and parameters of the Persian language and tested 24 native speakers’ claims on the statements in question. Results: The children judged sentence stimuli of two types (principles and parameters), each having two subcategories (Structure dependency and Projection principles, Head and Null-subjects (5-year-old) performance on principle- and parameter-judgments differed from their older counterparts (9-year-old), indicating the superior ability of the school-age group in distinguishing grammatically well-formed and ill-formed Persian principles and parameters. Conclusion: Since the older group attended elementary level (third grade), the interpretation of such results may pertain to education 09 25 2022 15 22 https://creativecommons.org/licenses/by/4.0 10.58803/jclr.v1i1.3 https://jclr.rovedar.com/index.php/JCLR/article/view/3 https://jclr.rovedar.com/index.php/JCLR/article/download/3/6 https://jclr.rovedar.com/index.php/JCLR/article/download/3/6 10.1037/h0033876 Chomsky, N. (1976). Reflections on language. (pp. 253-263). London: Temple Smith. Available at: https://philpapers.org/rec/CHOROL Chomsky, N. (1988). Language and problems of knowledge: the Managua lectures. Cambridge: Cambridge University Press, 56-80. Available at: https://b2n.ir/y59428 10.1515/9783110095869.1.9.506 10.1093/applin/6.1.2 Cook, V. J., & Newson, M. (1998). Chomsky’s universal grammar. U.S.A.: Blackwell Publishers. Available at: https://www.scribd.com/ document/527179585/Universal-Grammar-An-Introduction-3rd-Edition Cook, V. (2008). Second language learning and teaching. London: Hodder Education. 10.1016/j.sbspro.2011.10.260 Eliot, A. J. (1981). Child language. London: Cambridge University Press. Fletcher, P., & Garman, M. (1986). Language acquisition (2nd ed.). London: Cambridge University Press. DOI: https://doi.org/10.1017/ CBO9780511620683 Hosseini, M.R., Niroomand, H.A., & Moghaddaszadeh, B. (2007). Basic statistics. Iran: Jian. 10.1017/CBO9780511618963 10.1177/002383099704000102 10.1191/026765899667538959 10.1017/S0142716400003064 Richard, J. C., & Schmidt, R. (2002). Longman dictionary of language teaching and applied linguistics (4th ed.). UK: Longman Group. Available at: http://www.saint-david.net/uploads/1/0/4/3/10434103/linguistic_term_dictionary.pdf 10.2307/1127555 10.1017/S0305000900000684 10.1111/j.1540-4781.1996.tb01135.x 10.1177/0267658307082982