Which of the following best defines interlanguage?

• A. Incorrectly applying rules from L1 to L2
• B. Perfectly transferring L1 rules
• C. Only applies to pronunciation
• D. Is identical to L2 grammar

Answer: (A)

Interlanguage is the learner’s evolving, in-progress system of language use as they acquire a second language. It sits between the first language and the target language, shaped by the learner’s current hypotheses about how the language works. Because learners test out rules from their L1 in the process of forming L2 rules, their speech often shows patterns that reflect L1 influence and are not yet fully correct. That idea—students applying L1 rules to L2 in a way that isn’t quite right—best captures what interlanguage describes. It’s not simply a perfect transfer of L1, and it’s not limited to pronunciation, nor is it identical to the L2 grammar. Instead, it’s a dynamic, rule-governed system that develops with exposure and practice.