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Morpheme #7 of 14Brown's Stage III27–39 months

Uncontractible Copula

Uncontractible copula 'be' is the seventh of Brown's 14 morphemes, mastered between 27 and 39 months in obligatory non-contractible contexts.

At a glance

Acquisition order
#7 of 14 (Brown 1973)
Symbol / form
is/are/was (uncontractible)
Brown's stage
III
Typical age of mastery
27–39 months

Mastery is defined as correct use in 90% of obligatory contexts across three consecutive language samples (Brown 1973). Individual variation is wide — these ranges describe typically developing English-speaking children and should be cross-referenced against the primary literature before clinical use.

What this morpheme is

The copula is the verb "be" used as the main verb of a clause linking a subject to a predicate adjective, predicate nominal, or locative phrase. Brown distinguished two contexts for the copula: uncontractible, where the verb cannot be reduced to a clitic ("there it is", "yes I am", "where is it?"), and contractible, where it can ("he's tall"). He treated them as two separate morphemes in his 14 because they reach mastery on different timelines — uncontractible first, contractible second. The uncontractible context is the simpler one for children to learn because the copula cannot be dropped without producing an ungrammatical sentence, so the obligatory pressure is maximal.

Acquisition trajectory

Children begin producing copula "be" sporadically in late Stage II and reach 90% mastery in uncontractible contexts by approximately 39 months in typical development. Acquisition is verb-form-by-verb-form: "is" appears first, "are" follows shortly after, and "was/were" comes later. The clearest marker that uncontractible copula has been mastered is the production of forms like "there it is", "here she is", "yes it is" in response to questions — these are obligatory contexts where the copula cannot drop without producing a clearly ungrammatical utterance. Brown observed that children rarely substitute the wrong copula form (e.g., "is" for "are") in this period; the more common error is omission rather than substitution. Bilingual children whose other language has no copula equivalent (Russian, Arabic) may show extended omission of copula "be" in English without the pattern signalling a disorder, and the language sample should be interpreted in dialectal context.

Examples in obligatory context

These are the kinds of child utterances a clinician would code as a correct production of is/are/was (uncontractible) when scoring a language sample.

  • “There it is.”
  • “Here she is.”
  • “Yes I am.”
  • “Where is it?”
  • “It was big.”
  • “They are here.”

Common errors during the acquisition window

  • Omission in uncontractible context: "there it" for "there it is"
  • Substitution of bare stem "be" for an inflected form: "there it be"
  • Substitution of the wrong person/number: "there it are" for "there it is"
  • Persistent omission in question forms after declarative use is established

Many of these errors are developmentally normal during the acquisition window. The clinical signal is persistence past the typical age of mastery, not the presence of any single error in early production.

Clinical relevance and scoring

Uncontractible copula is one of the most sensitive morphemes for the Rice-Wexler extended-optional-infinitive profile in childhood DLD. Because the obligatory pressure in uncontractible contexts is maximal, omission here is a stronger signal than omission in contractible contexts. Score uncontractible copula in a language sample by identifying every obligatory context where contraction is not possible — typically clause-final position, response forms, and wh-question fronting — and coding each instance as correct, omitted, or substituted. Pair the score with the contractible copula score to get a complete picture of copula development. A child who omits both contractible and uncontractible "is" by 36 months is showing a grammatical pattern that warrants a full language evaluation.

“When a child says "there it" instead of "there it is", you are not looking at a hesitation — you are looking at the optional-infinitive stage that should have closed by 36 months. Score it, document it, and watch the rest of the tense system.”
No copula, no anchor

Free tools for scoring this morpheme

MLU Calculator

Paste a language sample and get Mean Length of Utterance in morphemes and words, total utterances, total morphemes, and the matching Brown's stage. Implements Brown (1973) morpheme counting rules and runs entirely in your browser.

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Brown's Stages Lookup

Interactive reference for Brown's (1973) five stages of grammatical development. Look up a stage by child age or MLU, see the MLU range, acquired morphemes, example utterances, and clinical milestones for each stage.

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DSS Calculator

Free Developmental Sentence Scoring (DSS) calculator for speech-language pathologists. Paste 50 sentences, tap weighted points across the eight Lee (1974) grammatical categories — Indefinite Pronouns, Personal Pronouns, Main Verbs, Secondary Verbs, Negatives, Conjunctions, Interrogative Reversals, Wh-Questions — plus the all-correct sentence point, and the calculator returns the live DSS with a per-category breakdown. Mobile-friendly tap-through grid, client-side, no sign-up.

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Related morphemes

#13 · Stage V+

Contractible Copula

Contractible copula 'be' is the thirteenth of Brown's 14 morphemes, mastered between 29 and 49 months in obligatory contractible contexts.

#12 · Stage V

Uncontractible Auxiliary

Uncontractible auxiliary 'be' is the twelfth of Brown's 14 morphemes, mastered between 29 and 48 months in obligatory non-contractible contexts.

#14 · Stage V+

Contractible Auxiliary

Contractible auxiliary 'be' is the fourteenth and last of Brown's 14 morphemes, mastered between 30 and 50 months and the last to reach criterion.

References

  1. Brown, R. (1973). A First Language: The Early Stages. Harvard University Press, pp. 337–367.
  2. Cleave, P. L., & Rice, M. L. (1997). An examination of the morpheme BE in children with specific language impairment: The role of contractibility and grammatical form class. JSLHR, 40(3), 480–492.
  3. Rice, M. L., & Wexler, K. (1996). Toward tense as a clinical marker of specific language impairment in English-speaking children. JSLHR, 39(6), 1239–1257.