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Morpheme #6 of 14Brown's Stage II26–40 months

Possessive 's

Possessive 's is the sixth of Brown's 14 morphemes, marking noun possession and mastered between 26 and 40 months in typical development.

At a glance

Acquisition order
#6 of 14 (Brown 1973)
Symbol / form
's
Brown's stage
II
Typical age of mastery
26–40 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

Possessive 's is the bound suffix that attaches to a noun to mark possession in English ("daddy's hat", "mommy's car"). Like the regular plural, it has three allomorphs — /s/, /z/, and /əz/ — and the child must control all three for full mastery. Brown placed it sixth in his order, reaching criterion in the second half of Stage II. It is the second possessive form English-speaking children acquire, after the unmarked juxtaposition pattern ("daddy hat") that appears earlier in Stage I.

Acquisition trajectory

The acquisition trajectory begins with the unmarked juxtaposition in Stage I and progresses to the suffixed form in late Stage II. Children typically produce the marked form first on highly familiar possessor names ("mommy's", "daddy's", their own name), then generalise to less familiar possessors. The /s/ allomorph after voiceless consonants is acquired earliest, /z/ after voiced consonants and vowels follows, and the syllabic /əz/ after sibilants is the last to be mastered. Brown noted that the possessive and plural -s morphemes do not develop in parallel despite their phonological similarity — children frequently produce one consistently while still omitting the other. Overgeneralisation to inappropriate contexts is rare; the more common error in the acquisition window is straightforward omission rather than substitution. Some children also produce the possessive pronoun system ("my", "your", "his", "her") and the suffixed possessive in the same sample, and the two should be coded separately.

Examples in obligatory context

These are the kinds of child utterances a clinician would code as a correct production of 's when scoring a language sample.

  • “Daddy's hat.”
  • “Mommy's car.”
  • “Baby's bottle.”
  • “The dog's toy.”
  • “I want Sarah's cookie.”
  • “That's the cat's bed.”

Common errors during the acquisition window

  • Omission of the possessive marker: "daddy hat" for "daddy's hat"
  • Failure to control the syllabic /əz/ allomorph after sibilants
  • Substitution with a possessive pronoun: "his hat" for "daddy's hat" (when the proper noun is required)
  • Inconsistent marking across possessors in the same sample

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

Possessive 's is moderately sensitive to DLD but less so than the tense markers. A child who consistently omits possessive 's while producing plural -s and present progressive -ing is showing a focal grammatical pattern that warrants follow-up but does not by itself meet criteria for a language disorder diagnosis. The unmarked Stage I form ("daddy hat") is developmentally appropriate up to about 30 months; persistence beyond that age in the absence of any suffixed productions is the relevant clinical signal. Score possessive 's in a language sample by identifying every obligatory context for nominal possession and coding for correct production, omission, or substitution with a possessive pronoun. Mastery is 90% across the three allomorphs combined per Brown.

“A 3-year-old who says "daddy hat" but "two cats" is not contradictory — possessive and plural are different morphemes that just happen to sound the same. Score them separately and the pattern usually clears up.”
Two suffixes, one sound

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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Language Sample Worksheet

Free printable and fillable language sample analysis worksheet for speech-language pathologists. Five columns (utterance #, transcription, morpheme count, grammatical Y/N, notes), configurable row count up to 100 utterances, browser print produces a clean PDF, and an inline running summary tracks total utterances, total morphemes, and rolling MLU as you fill it in.

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Related morphemes

#4 · Stage II

Regular Plural -s

Regular plural -s is the fourth of Brown's 14 morphemes, marking countable noun plurality and reaching mastery between 27 and 33 months.

#8 · Stage III

Articles ("a", "the")

The articles "a" and "the" are the eighth of Brown's 14 morphemes, mastered between 28 and 46 months as children learn definite versus indefinite reference.

#9 · Stage IV

Regular Past -ed

Regular past tense -ed is the ninth of Brown's 14 morphemes, marking past on regular verbs and reaching mastery between 26 and 48 months.

References

  1. Brown, R. (1973). A First Language: The Early Stages. Harvard University Press, pp. 298–322.
  2. de Villiers, J. G., & de Villiers, P. A. (1973). A cross-sectional study of the acquisition of grammatical morphemes in child speech. Journal of Psycholinguistic Research, 2(3), 267–278.
  3. Eisenberg, S. L., McGovern Fersko, T., & Lundgren, C. (2001). The use of MLU for identifying language impairment in preschool children: A review. American Journal of Speech-Language Pathology, 10(4), 323–342.