Speech and Language Milestones Every Praxis Candidate Must Know

Developmental norms are the backbone of every pediatric case on the Praxis 5331. The exam almost never asks "when does X emerge?" outright. It gives you an age and a behavior and asks whether it's typical, whether to refer, or what to target. That only works if the milestones are automatic.

Prelinguistic stages (0–12 months)

• 0–2 mo — reflexive vocalizations, crying, vegetative sounds
• 2–4 mo — cooing and gooing, social smile
• 4–6 mo — vocal play, squeals, raspberries
• 6–8 mo — canonical/reduplicated babbling ("bababa"). Absence by 9–10 months is a red flag for hearing loss.
• 8–12 mo — variegated babbling, jargon with adult-like intonation, joint attention, pointing, first word around 12 months

Toddler through preschool

• 12–18 mo — 10–50 words, follows simple one-step directions, uses gestures
• 18–24 mo — vocabulary spurt, two-word combinations around 50 words; ~50% intelligible to strangers
• 2–3 yr — 200–1,000+ words, 3-word phrases, "what/where" questions, ~75% intelligible
• 3–4 yr — 4–5 word sentences, tells simple narratives, asks "why", ~80–90% intelligible
• 4–5 yr — complex and compound sentences, follows 3-step directions, ~90–100% intelligible
• 5–6 yr — narrative structure with a story grammar, emerging phonological awareness, most grammatical morphemes mastered

Brown's stages and MLU

Mean length of utterance in morphemes maps to Brown's stages — expect at least one item on this.

• Stage I — MLU 1.0–2.0, ~12–26 mo, semantic relations
• Stage II — MLU 2.0–2.5, ~27–30 mo, grammatical morphemes begin
• Stage III — MLU 2.5–3.0, ~31–34 mo, questions and negation
• Stage IV — MLU 3.0–3.75, ~35–40 mo, embedded sentences
• Stage V — MLU 3.75–4.5, ~41–46 mo, coordination and conjoining

Brown's 14 grammatical morphemes emerge in a stable order: present progressive -ing, prepositions in and on, regular plural -s, irregular past, possessive 's, uncontractible copula, articles, regular past -ed, regular third person -s, irregular third person, uncontractible auxiliary, contractible copula, contractible auxiliary.

Play development (it's tested)

• Sensorimotor / exploratory — 0–12 mo
• Functional (uses objects appropriately) — 12–18 mo
• Symbolic / pretend — 18–24 mo
• Constructive and cooperative — 2–4 yr
• Games with rules — 5+ yr

Parten's social sequence — solitary, parallel, associative, cooperative — pairs with this and shows up in early-intervention cases.

Red flags that trigger a referral

• No babbling by 9 months
• No words by 15–16 months; fewer than 50 words or no word combinations by 24 months (late talker)
• Any loss of previously acquired skills at any age
• No response to name by 12 months, no joint attention by 12–14 months
• Unintelligible to strangers at 4 years
• Parental concern — by itself a valid reason to assess

A hearing screening precedes every speech-language referral; see audiology basics. For under-3s, services run through an IFSP — see early intervention.

How to memorize this fast

Anchor to the round numbers: 1 word at 12 months, 2-word combos at 24 months, 3-word phrases at 36 months, and intelligibility of roughly 50/75/100% at 2/3/4 years. Most items are answerable from those anchors alone. Our flashcard decks drill them one fact per card, and the child language development question set tests them in case format.