L2 — an abbreviation for ‘second language’ — any language learned after the first (L1), regardless of the order in which subsequent languages are acquired.

Definition

An abbreviation for ‘second language’ — any language learned after the first (L1), regardless of the order in which subsequent languages are acquired.

In Depth

An abbreviation for ‘second language’ — any language learned after the first (L1), regardless of the order in which subsequent languages are acquired.

In-Depth Explanation

L2 (second language) is the abbreviation used throughout applied linguistics and SLA research to refer to any language acquired after a person’s first language (L1), regardless of the order in which subsequent languages are learned. While the “2” in L2 suggests the second language chronologically, the term functions as a cover label in research for any non-native language being acquired at any point in life.

L1 / L2 / L3 distinction:

Why “L2” is used broadly:

In SLA research, “L2” functions practically as a contrast term to L1 — it marks the distinction between native-speaker acquisition (which follows a universal developmental path through childhood) and post-critical-period or instructed acquisition (which involves prior linguistic knowledge from L1). The number doesn’t matter: a person’s fifth language is still referred to as an “L2” in SLA research when the focus is on post-native acquisition processes.

L2 acquisition vs. L1 acquisition:

Key systematic differences between L1 and L2 acquisition:

L2 in the Japanese learning context:

For English L1 speakers learning Japanese, the L2 designation captures a striking contrast: Japanese and English are maximally different typologically (SOV vs. SVO; agglutinative vs. analytic; mora-timed vs. stress-timed; non-alphabetic vs. alphabetic script; extensive honorific system vs. minimal) making L1 English transfer effects on L2 Japanese acquisition particularly distinctive and extensively researched.

L2 proficiency:

L2 proficiency assessment framework (CEFR, JLPT, ACTFL) levels apply to L2 speakers. Even high-proficiency L2 speakers typically retain some non-native features in processing speed, pitch accent, metalinguistic judgements, and pragmatic norms — areas studied under the “native vs. non-native” research paradigm.

History

The L1/L2 distinction as a research framing emerged alongside the field of SLA in the 1960s–70s. Selinker’s (1972) concept of interlanguage — the systematic but non-native linguistic system of L2 learners — was foundational in establishing “L2” as a distinct research object. Krashen’s Monitor Model (1982) further popularised the L1/L2 acquisition distinction. The term L2 is now universal in linguistics, psycholinguistics, education, and cognitive science discussions of non-native language acquisition.

Common Misconceptions

• “L2 = the second language you ever learned.” In research contexts, L2 is a category term for any non-native language, not specifically the chronologically second language. A person with English L1 learning Japanese has Japanese as their “L2” whether it’s their second, third, or fourth language.
• “L2 speakers can never fully acquire native-like competence.” The attainment question is empirically contested. While full native-like competence is extremely rare in post-puberty starters, very advanced L2 speakers can achieve near-native competence in most domains. Early childhood sequential bilinguals (before ~5 years) often show native-like attainment.

Social Media Sentiment

“L2” as a term appears in linguistically informed language learning communities (r/LearnJapanese, polyglot YouTube) — it carries a slight academic register that marks awareness of SLA research. In general learner communities, “target language” or simply the language name is more common. Discussion of L1 vs. L2 differences (why Japanese is so hard for English speakers / why transfer effects occur) is consistent content. The L1/L2 framing is also used in polyglot discussion of how acquiring the third and subsequent languages relates to L2 acquisition research.

Last updated: 2026-04

Practical Application

• L1 transfer awareness: Knowing that L1 English shapes your L2 Japanese acquisition helps interpret specific difficulties as predictable rather than personal failure. English SVO habits create SOV processing challenges; the English article system has no Japanese equivalent; English stress-timing conflicts with Japanese mora-timing — these are transfer effects, not random errors.
• L2 processing speed: L2 Japanese processing will be slower than L1 English processing at any proficiency level except in very highly practised domains. This is normal; speed increases with exposure. Planning speaking time conservatively in Japanese conversations is a practical accommodation to this asymmetry.

Related Terms

• L1
• SLA
• Interlanguage
• Target Language
• L1 Transfer

See Also

Sakubo – Japanese App

Sources

• Selinker, L. (1972). Interlanguage. International Review of Applied Linguistics, 10(3), 209–231. Foundational paper introducing the concept of interlanguage — the systematic non-native linguistic system of L2 learners — establishing “L2 acquisition” as a distinct research domain.
• Gass, S. M., & Selinker, L. (2008). Second Language Acquisition: An Introductory Course (3rd ed.). Routledge. Standard SLA introductory textbook; defines and contextualizes the L1/L2 distinction, transfer effects, developmental sequences, and acquisition/learning debate.
• Muñoz, C. (Ed.). (2006). Age and the Rate of Foreign Language Learning. Multilingual Matters. Research collection on age effects in L2 acquisition; addresses the critical period hypothesis and the L1/L2 attainment distinction empirically.