Abdollahnejad, Elias2018-11-052018-11-052018-11-05Abdollahnejad, E. (2018). Competing grammars in language acquisition: the case of resumption in Persian relative clauses. In E. Abdollahnejad, D. Abu Amsha, K. Burkinshaw, A.D. Daniel, & B.C. Nelson (eds.), Calgary Working Papers in Linguistics, 30(Fall), 1-14.2371-2643http://hdl.handle.net/1880/108950Roeper (1999), Yang (2002), and Amaral and Roeper (2014) propose that all learners develop competing, even incompatible analyses of input as they work towards the target grammar. Using the term universal bilingualism, Roeper (1999) posits the existence of such Multiple Grammars (MG) and explores their role in first language acquisition. This paper discusses this proposal in the context of Persian children’s acquisition of resumption. In Persian, resumption is obligatory in object-of-preposition and genitive relative clauses (RCs) (Taghvaipour, 2005) and can be used optionally in subject and object RCs (Windfuhr, 2010). This behaviour makes it an appropriate construction to study the MG approach. Data from three Persian children (ages 1;11 to 4;2) in the CHILDES database (MacWhinney, 2000) were investigated for the frequency of RCs to see if there is a preference for resumption or gap in RCs. Results show that, in spite of variation in the received input, children prefer not to use resumption in subject and object RCs. However, 100% use of resumption in object-of-preposition and genitive RCs in their production data was observed. Despite optionality as a property of the input, children’s grammars appear to be categorical. Thus, children do not seem to be sensitive to variation in the input, which does not completely support Yang’s (2002) claim about the role of frequency of different forms in their dominance. The results confirm the presence of competing sub-grammars (resumption & gap) in both input and output from the early levels of language exposure and production.enrelative clauseresumptionmultiple grammarsVariational Learning ModelPersianFarsijournal article10.11575/PRISM/33245