Second Language Acquisition of Relative Clauses by Igbo-Speaking Learners of English: A Longitudinal Study

Relative clause acquisition in a second language presents a well-documented developmental challenge, and the influence of first language structural properties on the acquisition trajectory adds a language-specific dimension that requires empirical investigation in each learner population. This study examines the acquisition of English relative clauses by Igbo-speaking secondary school learners over a two-year longitudinal period in Ebonyi State, tracking the development of subject, object, oblique, and genitive relative clause types. A cohort of eighty Junior Secondary School students at two schools in Abakaliki was followed from JSS 2 through to SS 1, with oral and written production data collected at four six-month intervals using elicited production tasks and naturalistic writing samples. Cross-sectional data were complemented by grammaticality judgment tasks administered at each collection point. Developmental analysis drawing on the Noun Phrase Accessibility Hierarchy framework confirms a predominantly hierarchical acquisition order consistent with typological predictions, with subject relatives acquired earliest and genitive relatives last. However, significant departures from the predicted hierarchy are documented in the oblique-object relative ordering for this learner group, a pattern attributable to a specific mismatch between Igbo and English relative clause formation strategies at the oblique level. Longitudinal comparison across data collection points shows accelerating accuracy gains between data points two and three, coinciding with increased formal grammar instruction at the SS1 transition. Theoretical implications for the Noun Phrase Accessibility Hierarchy and pedagogical implications for relative clause instruction in Igbo-speaking learner populations are developed. Keywords: relative clause acquisition, second language acquisition, Igbo L1, longitudinal study, Ebonyi State.