Definition:
Subordination refers to the syntactic relationship in which a dependent (subordinate) clause is embedded within a main clause and depends on it for its full interpretation. Subordinate clauses are introduced by subordinating conjunctions (because, although, when), relative pronouns (who, which, that), or complementizers (that, whether, if), and they function as nouns (complement clauses), adjectives (relative clauses), or adverbs (adverbial clauses). Complex sentences with subordinate clauses form a fundamental part of advanced grammar in every language, and their mastery is a major milestone in both L1 acquisition and second language acquisition (SLA).
Types of Subordinate Clauses
1. Complement Clauses (Nominal Subordination):
A clause functioning as a noun — typically as subject or object:
- I know [that she left] — that-clause as object
- I wonder [whether it will rain] — whether-clause
- [That he lied] surprised everyone — subject clause
2. Relative Clauses (Adjectival Subordination):
A clause modifying a noun phrase:
- The book [that I read] — object relative clause
- The man [who called] — subject relative clause
- The city [where she grew up] — relative with locative head
3. Adverbial Clauses:
A clause expressing time, cause, condition, concession, or purpose:
- [When she arrived], the meeting started — temporal
- [Because he was tired], he left early — causal
- [If it rains], we’ll stay home — conditional
- [Although she tried hard], she failed — concessive
Phrase Structure — Hierarchical Embedding
Subordination creates hierarchical, recursive sentence structure. From an X-bar perspective, subordinate clauses are CP (Complementizer Phrases) that are embedded inside larger CPs or VPs:
“`
[ The student [ who [ the professor praised ] ] solved the problem ]
^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
NP Relative Clause (embedded CP)
“`
Finite vs. Non-Finite Subordinate Clauses
- Finite: Contains a tensed verb: I believe [that he is here]
- Non-finite:
Infinitival: She wants [to leave]
Participial: [Having eaten], she left
Gerundive: [Swimming every day] keeps her fit
Non-finite clauses in L2 show later acquisition because of the abstract control and movement relations involved.
L2 Acquisition of Subordination
Cross-linguistic research has established:
- Relative clause difficulty: The Noun Phrase Accessibility Hierarchy (Keenan & Comrie, 1977) predicts difficulty: subject relatives (the man who left) < object relatives (the man that I saw) < oblique relatives (the tools that she worked with) — in that order of increasing difficulty
- Complement clauses: Factive and non-factive distinctions interact with learner verb knowledge
- Cross-linguistic variation: English uses wh-movement to form relative clauses; some languages use gap strategies, others resumptive pronouns (the man that I saw him) — L1 transfer of resumptive pronouns is documented in L2 English
| L2 Challenge | Mechanism | Example Error |
|---|---|---|
| Missing relativizer | L1 head-final structure (no overt that) | The book I read was interesting. (acceptable but shows transfer of zero-relative) |
| Resumptive pronoun | L1 uses resumptive strategy | The man that I saw him was tall |
| Object relative processing | Heavier computational load | Significantly more errors on object relatives |
History
Subordination has been analyzed since classical grammar (Donatus, Priscian). Modern transformational approaches (Chomsky 1957, 1965) analyzed subordination as movement from embedded positions. Keenan & Comrie (1977) established the Noun Phrase Accessibility Hierarchy through cross-linguistic comparison.
Common Misconceptions
- “Subordinate clauses are optional” — Some are (adverbials), but complement clauses can be obligatory (I believe [that…] — the that-clause is a required argument of believe)
- “Relative clauses are just descriptions” — Relative clauses also perform restrictive functions that narrow reference
Criticisms
- The Noun Phrase Accessibility Hierarchy, while robust, has exceptions in some language types; some researchers argue for processing-load accounts over grammatical hierarchy
Social Media Sentiment
Language learners report complex sentences — especially relative clauses — as a major hurdle. Discussion of “when to use ‘that’ vs. ‘which’” is perennial. Last updated: 2026-04
Practical Application
- Sequence subordination instruction: start with when/because adverbial clauses, move to subject relative clauses, then object relative clauses — matching Noun Phrase Accessibility Hierarchy difficulty order
- Provide abundant comprehensible input with complex sentences to expose learners to the full range of embedding structures
Related Terms
- Phrase Structure
- Scrambling
- Word Order
- Head Directionality
- Second Language Acquisition
- Comprehensible Input
See Also
Research
- Keenan, E. L., & Comrie, B. (1977). Noun phrase accessibility and universal grammar. Linguistic Inquiry, 8(1), 63–99. — Foundational cross-linguistic hierarchy for relative clause difficulty.
- Hawkins, R. (2001). Second Language Syntax. Blackwell. — Comprehensive treatment of L2 acquisition of complex syntactic structures.
- Chomsky, N. (1965). Aspects of the Theory of Syntax. MIT Press. — Introduced phrase structure and embedding within transformational grammar.