MLU test

MLU (Mean Length of Utterance) is a measure used to assess a child's language development by calculating the average number of morphemes per utterance.

What counts as 1 morpheme

  • Free words: cat, run, the, Mommy

  • Compound words (learned as one unit): railroad, hotdog, basketball

  • Proper names (even if 2 words): Big Bird, New York

  • Diminutives: doggie, horsie, kitty

  • Irregular past tense (no -ed): went, ate, fell

  • Irregular plurals: men, children, mice

  • Catenatives (learned as one chunk): gonna, wanna, gotta

Bound morphemes (add +1 each)

  • Plural -s: cats (cat + -s)

  • Possessive ’s: Mommy’s (Mommy + ’s)

  • Third person singular -s: runs (run + -s)

  • Regular past -ed: walked (walk + -ed)

  • Progressive -ing: running (run + -ing)

  • Comparative -er / superlative -est: bigger (big + -er), biggest (big + -est)

  • Derivational prefixes/suffixes: unhappy (un- + happy), teacher (teach + -er), kindness (kind + -ness)

Contractions (common rules)

  • Copula/aux contractions = 2 morphemes: he’s (he + is/has), they’re (they + are), I’m (I + am), we’ve (we + have)

  • Negative contractions = 2 morphemes: don’t (do + not), can’t (can + not), isn’t (is + not), won’t (will + not)

  • Let’s = 2: let + us

Don’t count

  • Fillers/interjections: um, oh, mhm

  • False starts/mazes: I w- w- want… (count only the final form)

  • Imitations/rote forms (ABC song, memorized counting) if not spontaneous

  • Repetitions for emphasis: “No no no!” = 1 morpheme (“no”) unless each adds new meaning

Tricky cases (quick rulings)

  • “Ice cream”: if treated as a single lexical item by the child, count as 1; if clearly two words, count 2

  • “All gone/All done”: usually 2 morphemes (all + gone/done), unless transcribed as the unanalyzed form “allgone” and used that way consistently (then 1)

  • Numbers/dates/names spelled out: each word = 1 morpheme (twenty-one = 1 if written as a lexicalized compound; “twenty one” often 2)

  • Stutters/part-word repetitions: don’t count the fragments

Brown’s classic 14 (helpful for development tracking)

  1. -ing (present prog.)

  2. in

  3. on

  4. plural -s

  5. irregular past (went, came)

  6. possessive ’s

  7. uncontractible copula (He was happy.)

  8. articles (a, the)

  9. regular past -ed

  10. 3rd person -s (she runs)

  11. 3rd person irregular (does, has)

  12. uncontractible auxiliary (He was running.)

  13. contractible copula (He’s happy.)

  14. contractible auxiliary (He’s running.)

“Mommy’s cookies are baking.”

  • Mommy + ’s (2) | cookie + -s (2) | are (1) | bake + -ing (2) → 7 morphemes

What belongs in each stage and MLU range for that age:

  • Stage I (1-2 years, MLU 1.0-1.5): Simple two-word combinations (e.g., "more juice," "big truck")

  • Stage II (2-2.5 years, MLU 1.5-2.0): Emergence of grammatical morphemes (e.g., present progressive, plural)

  • Stage III (2.5-3 years, MLU 2.0-2.5): Use of auxiliary verbs and beginnings of complex sentences (e.g., "I am going")

  • Stage IV (3-3.5 years, MLU 2.5-3.0): More advanced verb forms and compound sentences (e.g., "I want cookies and milk")

  • Stage V (3.5-4 years, MLU 3.0-4.0): Use of conjunctions and complex sentence structures (e.g., "She said that she is coming").

MLU transcription

My/ want/ kitty mama - 4

yeah- 1

no hamid, he mine doggy- 5

me play dog mama - 4

(cries we dont count it as an utterance)

I wuv peppa -3

Peppa best friend name zoey -5

zoey a zebra -3

Mama, I need go poo-poo now - 6 (she thinks poo-poo, night-night, bye-bye as one)

actually my pooped in my pants - 7 pants are one

nope, my toot/ed - 4

giggled pause

my playing trick on you mama - 7

  • we count it as a coun because in her lanagueg it is one word such as doggy or peppa or nope

  • 49/11 = 4.5 

Don’t is one morpheme 

Ten points

PowerPoint slides MLU

Expressive Milesomes

On a Test: from our expressive milestones and what it is, she will say it on the test

Expressive Language Milestones

  • Birth–3 months: different cries for different needs; cooing, gurgle sounds

  • 3–6 months: vocalizes in response to caregiver imitation; engages in conversational turns; transitional babbling

  • 6–12 months: babbling continues; first word around first birthday; milestone: 1 word (average 5+ words); imitates sounds

  • 12–18 months: adult-like intonation; shows desire by pointing; 3–20 words (early vocabulary growth)

  • 18 months: ~10 words (average 50+ words by later timepoints)

  • 18–24 months: 50–100 words; 24 months: ~50 words; average ~300+ words; 2-word utterances; begin combining words; use pronouns more

Browns stages of development

Brown’s Stages of Development

  • Stage 1 (12–26 months)

    • Early: First words (MLU 1.0–1.5)

    • Late: Word-to-word combos (MLU 1.5–2.0)

  • Stage 2 (27–30 months)

    • Elaborating structure, refining meaning (MLU 2.0–2.5)

  • Stage 3 (31–34 months)

    • Longer, more adult-like sentences (MLU 2.5–3.0)

  • Stage 4 (35–40 months)

    • Phrases & clauses, embedding (MLU 3.0–3.75)

  • Stage 5 (41–46 months)

    • Polishing language (MLU 3.75–4.5)

Nuance

> means abandoned: one day my mom wanted to.. oh a butterfly

^ means interrupted: my mom wanted to, omg, there is a fire

x unintelligible: Gibberish words