Interlanguage
Is that a mistake, or a rule?
Interlanguage is the rule-governed, changing language system a learner builds on the way to a new language, different from both their first language and the target language.
Lan, a Year 9 student in Đà Nẵng, writes Yesterday I goed to the market and buyed some fish. Nobody taught her goed, and no English speaker around her says it. She has built a rule of her own and applies it consistently.
Larry Selinker (1972) gave this hidden system a name. Interlanguage is a separate linguistic system, inferred from a learner’s attempts to produce the target language, that differs from both the first language and the target. He traced it to processes such as first-language transfer, transfer of training, learning and communication strategies, and overgeneralising target-language rules, as goed shows. He also introduced fossilisation, the tendency of some forms to persist in a learner’s speech however much explanation and instruction they receive. Later reviewers such as Long (2003) questioned how much of the evidence shows permanent fossilisation rather than temporary stabilisation.
The system is not static: learners revise their rules as they meet more input. Its use also shifts with the task: Tarone (1983) showed that a learner may be more accurate when there is time to attend to form than in fast conversation. Research on developmental sequences, such as processability theory, adds that some stages are hard to skip.
For teachers, the shift is from counting mistakes to reading evidence. Corder (1967) argued that errors reveal the system a learner is currently using, so a form like goed can signal progress: a past-tense rule has been learned, even if it is over-applied. Feedback such as recasts or a brief focus on form works best when it targets the rule the learner is actually building.
In actionA rule at work
- T
- What did you do at the weekend, Minh?
- S
- I goed to Hội An with my family.
- T
- Oh, you went to Hội An! What did you eat?
- S
- We went to the old town and we eated cao lầu.
Minh’s goed and eated follow one rule: add -ed for the past. He picks up went from the teacher’s recast, but has not yet revised the rule for other irregular verbs.
In the classroom
- 1
Collect ten sentences from one learner’s speech or writing and look for patterns, not just errors: which forms recur consistently, and what rule could be producing them?
- 2
Separate one-off slips from systematic errors before giving feedback: ask the learner to self-correct first, since slips can usually be fixed on the spot while errors reflect current knowledge.
- 3
Compare the same learner on a careful written task and a timed speaking task, expect differences, and set goals for each condition rather than judging competence from a single sample.
Myth and reality
Learner errors are random lapses or bad habits carried over from the first language.
Many errors are systematic and reflect the learner’s current rules. Some come from the first language, but many, like goed, come from overgeneralising the target language itself, as children acquiring English as a first language also do.
Reflect
Which of your students’ most frequent errors might be evidence of a rule they have learned, and how would you respond if you treated it that way?
Worth a minute before your next lesson, or a conversation in the staffroom.
SourcesChecked against Crossref and library records
Selinker coined the term in 1972. Corder’s 1967 notion of ‘transitional competence’ and Nemser’s 1971 ‘approximative systems’ anticipated the idea that learner language has rules of its own.
Selinker, L. (1972). Interlanguage. IRAL: International Review of Applied Linguistics in Language Teaching, 10(1–4), 209–232.
Corder, S. P. (1967). The significance of learner’s errors. IRAL: International Review of Applied Linguistics in Language Teaching, 5(1–4), 161–170.
The short classic that recast errors as evidence of a learner’s developing system and distinguished systematic errors from slips.
Tarone, E. (1983). On the variability of interlanguage systems. Applied Linguistics, 4(2), 142–164.
Shows that learner language shifts systematically with the task, so one sample never tells the whole story.
Long, M. H. (2003). Stabilization and fossilization in interlanguage development. In C. J. Doughty & M. H. Long (Eds.), The handbook of second language acquisition (pp. 487–535). Blackwell.
A searching critique of fossilisation research and what would count as real evidence that learning has stopped.
Tarone, E. (2014). Enduring questions from the Interlanguage Hypothesis. In Z. Han & E. Tarone (Eds.), Interlanguage: Forty years later (pp. 7–26). John Benjamins.
Reads Selinker’s paper as a set of open questions and traces the research programmes they launched.
ConnectionsSee it in the graph
- Fossilizationnot yet writtenSelinker’s term for interlanguage forms that stop developing; its evidence is debated.
- Processability Theorynot yet writtenExplains why interlanguage grammar develops in a predictable order.
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