What does L1 interference refer to in language learning?

L1 interference refers specifically to the errors that learners make in a new language as a result of applying the grammatical rules, vocabulary, or pronunciation patterns from their native language (L1). When students learn a second language, they often unconsciously rely on their first language to construct sentences or communicate ideas. This reliance can lead to mistakes that reflect the structure or norms of the native language rather than the target language, which often results in sentences that may not be grammatically correct or idiomatic in the second language.

For instance, a Spanish-speaking learner might say "She has 20 years" instead of "She is 20 years old" because in Spanish, one says "Ella tiene 20 años," directly translating the grammatical structure of their native language into English. This shows how L1 interference manifests in language learning, highlighting that the influence of a learner's first language can significantly impact their competence in a second language.

The other choices describe different phenomena related to language learning but do not accurately define L1 interference. Positive influences from L1, blending of languages, and fluent bilingualism without errors represent other concepts, indicating that while students can benefit from their first language, interference specifically concerns the negative transfer of skills and structures.