Definition:
Third language acquisition (TLA) — also referred to as L3 acquisition or multilingual acquisition — is the process of acquiring an additional language by a person who has already acquired two prior languages (L1 and L2, or two simultaneous first languages). TLA is theoretically important because the learner brings two potential source languages for cross-linguistic influence, creating more complex transfer dynamics than in SLA (where only L1 is typically the source). A central question in TLA research is: which language — the L1 or the (usually more recently acquired) L2 — exerts greater structural influence on the developing L3? Answers to this question have implications for instruction, curriculum sequencing, and the nature of the multilingual mind.
How TLA Differs from SLA (L2 Acquisition)
| Dimension | L2 Acquisition (SLA) | L3 Acquisition (TLA) |
|---|---|---|
| Prior languages | 1 (L1) | 2+ (L1 and L2) |
| Transfer sources | L1 only (primarily) | L1 and/or L2 compete/combine |
| Learner type | Usually monolingual starting L2 | Bilingual starting L3 |
| Metalinguistic awareness | Lower | Higher (bilingual advantage in language learning) |
| Transfer selectivity | Mostly L1 | Dependent on typology, order, dominance |
Transfer Models in TLA
Several competing models address which language influences L3 the most:
1. Typological Primacy Model (Rothman, 2011)
The language most typologically similar to the L3 (regardless of whether it is L1 or L2) will be the primary transfer source at the initial stage of L3 acquisition.
2. L2 Status Factor (Hammarberg, 2001)
The L2 (most recently activated non-native language) is more likely to transfer than the L1 because it shares non-native status with the L3.
3. Cumulative Enhancement Model (Flynn et al., 2004)
Bilingual experience itself provides an advantage: having acquired two languages enhances the acquisition of a third, regardless of typology.
Cross-Linguistic Influence in TLA
Positive TLA transfer:
- A Spanish-English bilingual acquiring Italian benefits from Spanish grammatical gender, spatial prepositions, and verb paradigms (typological advantage)
Negative TLA transfer / Blended transfer:
- Some learners show blended transfer — a mix of L1 and L2 structures in the L3, creating novel interlanguage combinations
Multilingual Advantage
Research suggests that multilinguals learn additional languages more efficiently than monolinguals beginning SLA:
- Greater metalinguistic awareness
- More developed noticing and comparison strategies
- Stronger executive control (cognitive control over language selection)
History
TLA emerged as a distinct subfield of applied linguistics in the 1990s, with Cenoz, Hufeisen, and Jessner as leading figures. A focused research paradigm developed around the Typological Primacy Model, L2 Status Factor, and Cumulative Enhancement debates.
Common Misconceptions
- “L3 is just L2 acquisition again” — TLA involves qualitatively different dynamics due to multiple prior linguistic systems
- “The L1 always transfers most” — Evidence shows L2 can be the primary transfer source for L3, especially when L2 is typologically closer
Criticisms
- TLA models often studied in controlled, relatively artificial conditions; generalizability to naturalistic L3 immersion is debated
- Dominant language and proficiency in each prior language are difficult to fully control across studies
Social Media Sentiment
Third-language learners often report confusion about whether their L2 “gets in the way” of new languages — this is a very common phenomenological observation in language learning communities, especially among polyglots. Last updated: 2026-04
Practical Application
- When designing L3 instruction, acknowledge that learners’ most typologically similar prior language (whether L1 or L2) will be a resource — teach learners to leverage that systematically
- Bilingual learners beginning a third language should be encouraged to use their prior language knowledge as a scaffold rather than treating all languages as separate silos
Related Terms
See Also
Research
- Rothman, J. (2011). L3 syntactic transfer selectivity and typological determinism: The Typological Primacy Model. Second Language Research, 27(1), 107–127. — Foundational statement of the Typological Primacy Model.
- Hammarberg, B. (2001). Roles of L1 and L2 in L3 production and acquisition. In J. Cenoz, B. Hufeisen, & U. Jessner (Eds.), Cross-linguistic Influence in Third Language Acquisition. Multilingual Matters. — Empirical evidence for L2 Status Factor.
- Cenoz, J., Hufeisen, B., & Jessner, U. (Eds.) (2001). Cross-linguistic Influence in Third Language Acquisition. Multilingual Matters. — Core edited volume establishing TLA as a research field.