Transformative impacts of explicit morphological instruction on irregular inflectional acquisition in Saudi EFL learners

Arabic and English differ substantially in morphology—Arabic is largely non-concatenative, relying on internal vowel changes and consonant patterns, while English morphology is primarily concatenative. Saudi EFL learners often struggle with English irregular forms (e.g., go→went; run→ran) because these do not follow transparent rules familiar from Arabic morphology. These differences warrant exploration of explicit morphological instruction to address learners’ difficulties and enhance L2 acquisition. The study is motivated by Input Processing Theory (VanPatten, 1996), which posits that explicit instruction can aid learners’ processing of complex input, and Processability Theory (Pienemann, 1998), which emphasises developmentally sequenced acquisition supported by instruction that scaffolds learners through stages. Explicit rules, focused practice, error correction, and feedback are hypothesised to help bridge Arabic–English morphological differences for Saudi learners. Explicit morphological instruction, defined as providing clear explanations, rules, and examples (Zhong & Zhang, 2023), has shown promise in various domains, yet its impact on irregular inflectional forms among EFL learners—particularly in Saudi Arabia—remains underexplored. Given potential influences of learners’ linguistic and cultural background, the study examines whether explicit instruction supports acquisition of irregular inflectional forms and their transfer to writing. Aims: to investigate the transformative effects of explicit morphological instruction on Saudi EFL learners’ acquisition of irregular inflectional forms, including transfer to writing, under the theoretical lenses of Input Processing Theory and Processability Theory. Prior work indicates explicit instruction improves grammatical accuracy and vocabulary learning (e.g., Suzuki et al., 2023; Dickinson et al., 2019), reinforcing the study’s rationale.

Theoretical framework: Input Processing Theory (VanPatten, 1996) highlights learners’ cognitive mechanisms (attention, perception, memory) in processing input and supports explicit instruction to enhance accuracy in producing target forms. Evidence indicates that explicit exposure facilitates form acquisition and retention (Schmidt, 1990; Fotos, 1994; Swain, 1998; Khan, 2022). Processability Theory (Pienemann, 1998) describes developmental stages of L2 acquisition and posits that instruction aligned to these stages promotes advancement to more complex structures. Recent studies guided by PT show explicit instruction aids morphological acquisition (e.g., Schenck, 2022). Literature review: Inflectional morphology links form and meaning through affixation and internal vowel changes; it differs from derivational morphology in not changing lexical category (Nordquist, 2015; Aikhenvald, 2007). English employs various inflectional mechanisms (comparatives/superlatives, possessives, tense/aspect morphology, plurals including irregular forms), whereas Arabic morphology is highly inflectional, often discontinuous, and based on consonantal roots with templatic vowel patterns (Shamsan & Attayib, 2015). Structural contrasts (e.g., lack of do-support in Arabic, VSO vs. English SVO) can contribute to EFL learner difficulties. Explicit morphological instruction has been shown to support adult EFL learners, who rely more on explicit learning (DeKeyser, 2000, 2003; Ullman, 2001, 2004; Ellis, 2005, 2009). Studies indicate that form-focused, explicit interventions can enhance morphological awareness, vocabulary breadth, reading comprehension, and writing (Norris & Ortega, 2000; Spada & Tomita, 2010; Goo et al., 2015; Brimo, 2016; Badawi, 2019; Crosson et al., 2019; Kieffer & Lesaux, 2012; Lee & Choi, 2020; Khan, 2022). Evidence suggests explicit instruction improves recognition and use of morphemes (Schuwerk, 2004; Ross & Berwick, 1991), and morphological knowledge underpins spelling, grammar, vocabulary, and writing quality (Masrai, 2016; Karimi, 2013; Crossley & McNamara, 2009, 2012; Engber, 1995; Ginsberg et al., 2011). Meta-analytic work (Goldschneider & DeKeyser, 2001) reports robust orders of L2 morpheme acquisition influenced by input properties. Research gap: Despite related work on tense and plural morphology in other L1 contexts (e.g., Japanese, Korean, Chinese), the transformative effects of explicit instruction on English irregular inflectional morphology for Arabic-speaking EFL learners—particularly transfer from recognition to writing—remain under-studied. The present study addresses this gap and formulates three hypotheses concerning group differences, recognition gains, and transfer to writing.

Design: Pretest–posttest quasi-experimental design with a control group (Group 1) receiving routine English lessons and an experimental group (Group 2) receiving additional explicit instruction on irregular inflectional morphemes. Regular English classes were 1.5 hours, four days per week, using Q: Skills (OUP) aligned with CEFR. Participants and sampling: Convenience sample of 69 native Arabic-speaking Saudi male EFL learners (ages 19–20) in the medical track, English Language Skills Department (Common First Year), King Saud University. All had ~12 years of school English and were placed at CEFR Level B via the Oxford Quick Placement Test. Groups: Group 1 (n=32), Group 2 (n=37). Ethical approval and informed consent obtained. Intervention: One-hour session per week for seven consecutive weeks (without disrupting regular classes). Weeks 2–6 delivered explicit instruction on irregular inflectional morphology using visual aids (charts, diagrams, infographics) and metalinguistic discussion (pair/group analysis of rules, exceptions). PowerPoint presentations included examples such as go–went, eat–ate, give–gave, take–took, come–came, see–saw, break–broke, bring–brought, speak–spoke, write–wrote, sing–sang, fly–flew. Week 7: posttest. Instructional content drew on Yule (2020), ch. 6 (‘Morphology’), and online materials. Instrumentation: Grammaticality Judgement Tasks (GJT) and written sentence assignments (Appendix A). Pretest: 20 sentences (10 with correct irregular inflections; 10 with incorrect forms) plus 20 words for morpheme recognition/knowledge. Learners identified correct/incorrect morphemes and wrote one correct sentence per target word (open-ended) to assess transfer to writing. Posttest paralleled pretest. Procedures and analysis: Sessions scheduled weekly (12–1 PM, Wednesdays). Data analysed with SPSS using descriptive stats and inferential tests (t-tests; “one-sample” tests against a test value of 0 as reported) to compare groups’ pre/post performance in (1) vocabulary knowledge, (2) morpheme recognition, (3) morpheme use in writing. Reliability: Cronbach’s alpha indicated strong internal consistency; test materials were validated by three EFL PhDs.

• Across vocabulary knowledge, morpheme recognition, and morpheme use in writing, statistical tests yielded p-values < 0.001, rejecting null hypotheses and supporting significant effects of instruction.
• Vocabulary knowledge: Reported means around 1.30–1.39 across subgroups; tests against a zero test value produced highly significant t-values (e.g., t=40.761 to 78.780; p<0.001), indicating substantial gains relative to the benchmark and significant group differences post-instruction.
• Morpheme recognition: Control Group_1 mean=1.3461 (SD=0.0998); Control Group_2 mean=0.5563 (SD=0.1470). Experimental Group_1 mean=1.3405 (SD=0.1137); Experimental Group_2 mean=0.3676 (SD=0.1929). One-sample tests showed all p<0.001 (e.g., t=76.284; t=21.404; t=71.713; t=11.589). The experimental group outperformed the control on recognition consistent with explicit instruction effects.
• Morpheme use in writing: Control Group_1 mean=0.5297 (SD=0.1679); Control Group_2 mean=0.5828 (SD=0.2448). Experimental Group_1 mean=0.2722 (SD=0.2395); Experimental Group_2 mean=0.4622 (SD=0.2851). All tests p<0.001 (e.g., t=17.842; t=13.467; t=6.820; t=9.859), indicating significant differences from the test value and improvements consistent with transfer to writing in the experimental group.
• Qualitative evidence: Pretest writing contained numerous irregular plural and tense errors (e.g., childrens, gooses, leafs, buyed, sheeps). Posttest examples showed correct use (e.g., mice, geese, leaves, bought), indicating successful transfer of irregular forms to production.
• Overall, explicit morphological instruction significantly improved learners’ vocabulary knowledge of target forms, recognition of irregular inflections, and correct use in writing, aligning with Input Processing Theory and Processability Theory.

Findings demonstrate that explicit morphological instruction enables Saudi EFL learners to process and produce irregular inflectional forms more accurately. The significant improvements answer the research questions by showing (1) reliable posttest differences between groups, (2) superior morpheme recognition in the experimental group attributable to overt instruction and practice, and (3) transfer to writing evident in improved production accuracy. Errors common in the pretest—rooted in Arabic–English morphological contrasts and overgeneralisation—were substantially reduced after instruction. These outcomes corroborate Input Processing Theory: explicit explanation and attention-directing activities enhance intake and form–meaning mapping. They also support Processability Theory: structured, scaffolded practice facilitates progression through developmental stages toward productive control of morphology. The convergence with prior research on explicit/form-focused instruction and morphological awareness underscores the pedagogical value of explicit morphology teaching for adult EFL learners.

Pretest–posttest comparisons between control and experimental groups show that explicit instruction in irregular inflectional morphology significantly facilitates L2 learning, with strong effects across vocabulary knowledge, morpheme recognition, and written production (all p<0.001). The results substantiate the roles of Input Processing Theory and Processability Theory in accounting for how explicit, visually supported, and metalinguistic instruction enhances learners’ processing and production of irregular forms. The study contributes evidence that explicit instruction improves recognition and supports transfer to writing for Arabic-speaking EFL learners. Future work should examine effects on speaking, listening, and reading; replicate with learners of other L1 backgrounds and schooling levels; and include female participants to broaden generalisability. Pedagogically, integrating visual aids and metalinguistic discussion into form-focused instruction can enhance input processing and developmental progress in morphology.

• Sample characteristics: All participants were male Saudi undergraduates from a single institution and program; convenience sampling and quasi-experimental grouping may limit generalisability.
• Scope and duration: Short intervention (one hour weekly for seven weeks) focused specifically on irregular inflectional morphology; effects on other skills (speaking, listening, reading) were not directly measured.
• Assessment design: Reliance on GJT and written sentence tasks; statistical reporting used one-sample t-tests against a test value of zero, which may not fully capture between-group contrasts despite reported significant differences.
• Context specificity: Instructional materials and procedures (e.g., selected verb sets, visual aids) may not generalise across curricula or proficiency levels without adaptation.