Definition:
Larry Selinker is an American applied linguist whose 1972 paper “Interlanguage” is one of the most cited and influential publications in the history of second language acquisition research. In that paper, Selinker introduced the concept of interlanguage — the systematic, rule-governed linguistic system that L2 learners construct during acquisition, which is distinct from both the learner’s L1 and the target language. Selinker also introduced the term and concept of fossilization — the phenomenon whereby certain interlanguage features become permanent, ceasing to develop even under continued exposure and instruction. These two concepts reframed SLA from a study of “errors to be corrected” into a study of “developing systems to be understood.”
Full name: Larry Selinker
Institution: New York University; University of London
In-Depth Explanation
The interlanguage paper (1972).
Selinker’s 1972 paper in IRAL (International Review of Applied Linguistics) is the founding document of modern SLA as a field. Its core argument:
- L2 learner language is not simply incorrect target language with random errors. It is a systematic linguistic system — a grammar in its own right — with identifiable rules and patterns.
- This system — which Selinker named interlanguage (IL) — is psycholinguistically distinct from both the L1 and the target L2. It has its own structure at any given developmental stage.
- Interlanguage develops over time through a predictable sequence of stages as the learner’s internal grammar is progressively restructured toward (but often not reaching) the target grammar.
- The evidence: learner errors are not random, they are orderly and interpretable. Errors made by learners from different L1 backgrounds share systematic features; errors from the same L1 background share other systematic features.
This framework transformed SLA research. Error analysis shifted from identifying “mistakes to fix” to mapping developmental stages and inferring the underlying interlanguage grammar from learner production.
Five interlanguage processes.
In the 1972 paper, Selinker proposed five central psycholinguistic processes that shape interlanguage development:
- Language transfer: Features of the L1 are transferred into the interlanguage. When the L1 and L2 differ, this produces negative transfer (errors); when they are similar, positive transfer (facilitation).
- Overgeneralization of target language rules: Learners extend a rule beyond its appropriate domain. A learner who knows the English past tense rule -ed overapplies it: goed, runned, breaked instead of went, ran, broke.
- Transfer of training: Features appear in interlanguage because they have been specifically taught and practiced — the artifact of the instructional sequence rather than the learner’s natural development.
- Strategies of L2 communication: Learners deploy communicative strategies — simplification, avoidance, approximation — to communicate despite gaps in their interlanguage. These strategies shape the IL.
- Strategies of L2 learning: The conscious or unconscious strategies learners use to learn the L2 (hypothesis testing, rote memorization, pattern matching) influence what gets incorporated into the IL.
Fossilization.
Selinker’s second major contribution was theorizing fossilization — a central puzzle in adult SLA. He observed that most adult L2 learners, regardless of instruction, motivation, or exposure, stabilize at a permanently non-native state. Certain features of their interlanguage become fossilized: they do not change further, persist under correction, re-emerge after periods of correct performance, and resist even deliberate remediation.
Selinker proposed that fossilization reflects the latent language structure hypothesis: adult L2 learners are using general cognitive mechanisms for L2 acquisition, not the specialized language acquisition device available to children. Only approximately 5% of adult L2 learners achieve native-level competence. This low rate is explained by the inaccessibility (or reduced accessibility) of the innate language faculty after the critical period (see Critical Period Hypothesis and Universal Grammar).
Subsequent development and debates.
Selinker’s interlanguage framework has been refined, challenged, and extended in several directions:
- Variability: Subsequent research (Tarone, Ellis) showed that interlanguage is not a single fixed system but a variable range — learners use different forms in different contexts (formal vs. casual). This complicates the “systematic interlanguage” picture.
- Reconceptualizing fossilization: Later researchers including Han and Odlin have argued for more nuanced accounts, distinguishing stabilization (temporary plateau) from fossilization (permanent stopping), and questioning whether fossilization is ever truly permanent.
- Dynamic Systems Theory: Larsen-Freeman and others have incorporated interlanguage development within dynamic systems / complexity theory frameworks, modeling IL development as a non-linear, self-organizing system rather than a linear developmental sequence.
History
Larry Selinker is an American applied linguist whose career centered primarily at the University of Michigan and later New York University. His doctoral training was in linguistics and he was influenced by transformational-generative grammar while working in the context of the applied linguistics paradigm developing at the time. The 1972 interlanguage paper emerged from a research agenda examining why adult L2 learners persistently produce systematic non-native-like utterances — a phenomenon Selinker traced to five psycholinguistic processes. The paper’s influence was transformative: it reoriented SLA research from error analysis (which focused on L1-based interference errors) to the broader study of interlanguage as a systematic developmental linguistic system. Selinker later collaborated with John Lamendella on fossilization (1979) and with Zhaohan Han on longitudinal fossilization research (2001), refining theoretical claims about which aspects of interlanguage resist change and under what conditions.
Key Contributions
- Interlanguage concept and terminology
- Fossilization concept and terminology
- Framework of five IL processes (transfer, overgeneralization, transfer of training, communication strategies, learning strategies)
- Establishing SLA as an autonomous field of research with its own theoretical framework
Research
Selinker, L. (1972). Interlanguage. IRAL — International Review of Applied Linguistics in Language Teaching, 10(1–4), 209–232.
The foundational paper introducing the interlanguage construct — proposing five psycholinguistic processes (language transfer, transfer of training, L2 learning strategies, communication strategies, overgeneralization) that produce the systematic non-target-like L2 system, and establishing interlanguage fossilization as a defining theoretical concept for SLA research.
Selinker, L. (1992). Rediscovering Interlanguage. London: Longman.
Selinker’s book-length expansion and refinement of interlanguage theory — revisiting the original 1972 claims in light of two decades of SLA research and extending the framework to accommodate subsequent empirical findings about L2 developmental patterns.
Selinker, L., & Lamendella, J. T. (1979). The role of extrinsic feedback in interlanguage fossilization. Language Learning, 29(2), 363–375.
Research examining the conditions under which external feedback affects interlanguage development or fossilization — exploring whether and how error correction disrupts stable non-target-like fossilized forms in learner interlanguage.
Selinker, L., & Han, Z. (2001). Fossilization: Moving the concept into empirical longitudinal study. In C. Elder et al. (Eds.), Experimenting with Uncertainty: Essays in Honour of Alan Davies. Cambridge University Press.
Selinker’s later work with Han examining fossilization empirically — refining the theoretical characterization of what constitutes genuine fossilization versus temporary stabilization in interlanguage development.
Common Misconceptions
“Fossilization means permanent failure to acquire target-like forms.” Selinker’s concept of fossilization was originally defined as the permanent cessation of L2 development in specific structures — but subsequent research has challenged whether true “permanent” fossilization is empirically distinguishable from long-term stabilization. Learners who appear fossilized may show renewed development with intensive instruction or changed input conditions. Contemporary SLA uses “stabilization” for persistent non-target-like forms and reserves “fossilization” for forms that appear genuinely impervious to change.
“Interlanguage = broken L2.” Interlanguage is not deficient language — it is a systematic, rule-governed linguistic system with its own internal logic. Interlanguage errors are not random mistakes but reflect productive application of learner-internal rules, L1 transfer, overgeneralization, and strategy use. The interlanguage framework was explicitly designed to treat learner language as a coherent system worthy of linguistic description, not as a deviation from native-speaker norms.
Criticisms
Selinker’s interlanguage framework has been criticized for the theoretical imprecision of the five psycholinguistic processes — the categories overlap, and distinguishing, for example, “learning strategies” from “communication strategies” or “transfer of training” from “L2 learning strategies” is not always analytically clean in empirical research. The fossilization concept has faced the specific critique that it is methodologically unfalsifiable without longitudinal data over very long periods — stabilization that persists for years could always potentially change, making the criterion for “permanent” fossilization empirically problematic.
Social Media Sentiment
Larry Selinker’s concepts — primarily interlanguage and fossilization — are encountered by language learners primarily through applied linguistics courses and SLA-adjacent reading rather than as primary community topics. The concept of “fossilized errors” resonates with learners who notice persistent mistakes that don’t respond to correction, and “interlanguage” as a framing for the systematic developmental stage before target-like proficiency is used in teacher education and advanced learner communities. The broader SLA framework his work inaugurated is the foundation of academic discourse about why adults struggle with certain L2 features.
Last updated: 2026-04
Practical Application
The interlanguage framework implies that L2 errors are systematic and diagnosable — not random failures. For learners, this means error tracking and analysis is valuable: identifying persistent non-target-like patterns (potential fossilization candidates) and targeting them with explicit study or intensive corrective input.