Developmental Sequence

Definition:

A developmental sequence is a predictable, ordered set of stages through which language learners pass when acquiring a specific grammatical structure or target language (TL) feature. A key finding from decades of SLA research is that developmental sequences are largely invariant — learners must pass through stage N before reaching stage N+1, and cannot “leapfrog” stages even with explicit instruction. Sequences are also largely universal: learners with very different first languages (L1s) follow the same developmental stages for the same TL features, suggesting that acquisition is constrained by cognitive and linguistic universals, not L1 structure alone.

Also known as: Acquisition orders, developmental stages, morpheme order, acquisitional sequences

The Morpheme Order Studies

The earliest systematic evidence for developmental sequences came from the morpheme order studies of the early 1970s. Roger Brown (1973) documented that children acquiring English as a L1 acquired 14 grammatical morphemes (such as -ing, plural -s, copula be, third-person -s) in a consistent order. This was followed by cross-sectional research with L2 learners:

Dulay and Burt (1974) found that Spanish-speaking and Chinese-speaking children learning English as an L2 acquired the same 8 morphemes in a nearly identical order — despite having very different L1s. This was striking evidence that developmental order was not simply determined by L1 difficulty predictions from Contrastive Analysis.

The widely replicated English morpheme acquisition order:

1. -ing (present progressive)
2. Plural -s
3. Copula be
4. Articles (a, the)
5. Irregular past tense (went, came)
6. Regular past -ed
7. Third-person singular -s
8. Auxiliary be

Negation and Question Development in English

Developmental sequences have been most extensively studied in negation and question formation. For English negation, learners consistently pass through four stages:

Question development also follows an invariant sequence (from no inversion, through fronting, to full inversion with auxiliary).

German Word Order Sequence

Pienemann and colleagues documented a robust developmental sequence for German word order, crucial to the development of the Processability Theory:

Processability Theory and Teachability

Developmental stages vs. morpheme order.

The morpheme order studies (cross-sectional, comparing learners at different proficiency levels) are sometimes conflated with developmental stage research (longitudinal, tracking individual learners over time). Both reveal systematic sequences, but with different granularity:

• Morpheme order: A rank-ordering of when specific morphemes reach 90% accurate production in obligatory contexts — a snapshot of relative difficulty.
• Developmental stages: A sequence of qualitatively distinct stages through which learners pass — each stage characterized by distinct interlanguage rules.

Processability Theory (PT) (Pienemann, 1998) explains WHY developmental sequences exist: to produce a grammatical structure, learners need the cognitive processing machinery to hold and exchange certain grammatical information. This machinery becomes available only in a fixed order. PT makes a strong pedagogical claim — the Teachability Hypothesis: instruction can only produce acquisition when the learner is developmentally ready for the next stage. Teaching structures that are many stages ahead of the learner’s current processing capacity will not result in acquisition.

Japanese Developmental Sequences

Japanese L2 acquisition research has documented developmental stages for several structures:

• Relative clauses: Learners pass through stages from unmarked object-modifying relative clauses to more complex subject-modifying and internally-headed relative clauses in a consistent order.
• Verb morphology: Acquisition of verbal inflections follows predictable patterns — present/non-past forms before past forms; polite (masu) forms often acquired before plain forms in instructed learners, but plain forms may be needed for natural reading comprehension before they reach accuracy in production.
• Particles: Topic marker は and object marker を are acquired in somewhat different trajectories; learners frequently omit or substitute particles in predictable ways at early stages.
• Negation: Sentence-final negation (ない/ません) before mid-sentence negation; learners tend to negate at the clause boundary before acquiring more structurally embedded negation.

Implications for Instruction

Developmental sequences have profound implications for language teaching:

1. Syllabus design must account for natural acquisition orders — teaching items in textbook order (often driven by formal simplicity) may not match developmental readiness
2. Error correction of stage-typical errors may be futile if the learner is not yet ready to acquire the next stage
3. Formative assessment and diagnostic tests should track developmental stage, not just accuracy percentages
4. Spontaneous production reflects developmental stage more accurately than performance on decontextualized tests

History

• 1973: Roger Brown publishes A First Language — documents consistent morpheme acquisition order in L1 English learners.
• 1973–74: Dulay & Burt demonstrate a similar (though distinct) acquisition order for L2 English learners — the “creative construction” hypothesis.
• 1977–83: ZISA project (Clahsen, Meisel, Pienemann) documents six-stage German word order developmental sequence for L2 learners.
• 1978: Cancino et al. document negation sequences longitudinally.
• 1984: Pienemann publishes the Teachability Hypothesis — pedagogical implications of developmental sequences.
• 1985–87: Johnston and Pienemann establish the German word order sequence formally.
• 1998: Pienemann publishes Language Processing and Second Language Development: Processability Theory — the full theoretical account of why developmental sequences exist.
• 2000s–present: Processability Theory applied to Japanese, Arabic, Swedish, and other languages; debate continues about the universality of sequences and the extent to which they can be influenced by instruction.

Common Misconceptions

• “Instruction can change developmental order” — Intensive instruction can compress the time spent at a stage but cannot eliminate the sequence
• “Adults follow different sequences than children” — For many structures, L1 children and L2 adults show common developmental sequences, though rate differs
• “Developmental sequences only apply to morphology” — While morpheme order studies are the most famous, developmental sequences have been documented for syntax (relative clauses, negation, interrogatives, word order), phonology (L2 phoneme acquisition stages), and vocabulary (depth of lexical knowledge development is also staged)

Criticisms

Research on developmental sequences has been criticized for over-reliance on data from English L2 acquisition and a small set of morphosyntactic features. Generalizability to other target languages, less-studied L1-L2 combinations, and non-morphosyntactic features (pragmatics, lexical development, phonology) is far from clear. The claim that developmental sequences are invariant and cannot be altered by instruction has been partially revised: while sequences cannot be skipped wholesale, instruction appears to affect the rate of movement through stages and the robustness of forms at each stage. Processability Theory has been critiqued for not fully explaining developmental sequences in languages with very different typological properties. Methodological critiques include over-reliance on single production tasks and group-level data that may obscure significant individual variation.

Social Media Sentiment

Developmental sequences are discussed in applied linguistics and language teacher education communities, though they rarely surface in general language learning discussions. The practical implication — that certain grammatical structures are learned before others regardless of instruction order — is relevant for curriculum design but abstract for individual learners. Teachers encounter the concept when students “cannot” learn a form they have been taught repeatedly, which is often attributable to developmental prerequisite structures not yet being acquired. The teachability hypothesis resonates with teachers who observe the phenomenon even without knowing the formal theory. Last updated: 2026-04

Practical Application

• Don’t beat yourself up over stage-appropriate errors — they are signs of normal development, not failure
• Use comprehensible input at or slightly above your current developmental stage (i+1, per Krashen’s Input Hypothesis)
• Extensive listening and graded readers at stage-appropriate level facilitate developmental progress more reliably than structural drilling alone
• For L2 Japanese learners, awareness of acquisition sequence research suggests prioritizing forms shown to develop earlier (e.g., te-form constructions, basic noun modification) before more complex structures like conditional forms or causative-passive combinations

Related Terms

• Natural Order Hypothesis
• Interlanguage
• Processability Theory
• Input Hypothesis
• Contrastive Analysis
• Formative Assessment
• Metalinguistic Awareness

See Also

• Affective Filter Hypothesis
• Monitor Hypothesis
• Task-Based Language Teaching
• Focus on Form
• Sakubo

Research

1. Brown, R. (1973). A First Language: The Early Stages. Cambridge, MA: Harvard University Press.

The foundational study documenting consistent morpheme acquisition order in three L1 English-acquiring children.

2. Dulay, H., & Burt, M. (1974). Natural sequences in child second language acquisition. Language Learning, 24, 37–53.

The landmark L2 morpheme order study demonstrating that Spanish- and Chinese-speaking children acquiring English L2 show a remarkably similar morpheme acquisition order.

3. Pienemann, M. (1984). Psychological constraints on the teachability of languages. Studies in Second Language Acquisition, 6(2), 186–214.

The original teachability hypothesis paper establishing the pedagogical implications of developmental sequences.

4. Pienemann, M. (1998). Language Processing and Second Language Development: Processability Theory. Amsterdam: John Benjamins.

The full theoretical account of why developmental sequences exist, grounded in speech processing architecture.

5. Kawaguchi, S. (2005). Argument structure and syntactic development in Japanese as a second language. In M. Pienemann (Ed.), Cross-linguistic Aspects of Processability Theory (pp. 253–298). Amsterdam: John Benjamins.

Extension of Processability Theory to Japanese L2 development, documenting developmental sequences for Japanese syntactic structures.

• Brown, R. (1973). A First Language: The Early Stages. Harvard University Press. — Established the morpheme acquisition order for L1 English.
• Dulay, H., & Burt, M. (1974). Natural sequences in child second language acquisition. Language Learning, 24(1), 37–53. — Showed L2 learners follow common morpheme order regardless of L1.
• Pienemann, M. (1998). Language Processing and Second Language Development: Processability Theory. John Benjamins. — Theoretical account of why developmental sequences are invariant; Teachability Hypothesis.