Language Development:

Perlocutionary Period (0–8 months)

- Unintentional communication

Reflexive Vocalizations (0–2 months)

• Sounds reflect automatic responses of the body

• Defined by anatomy of child (e.g., burping, crying, etc.)

• Nasalized vowel-like sounds with minimal resonance

Cooing (2–4 months)

• Sounds made in back of mouth

Vocal Play (4–6 months)

• Raspberries, growls, squeaks

• Begin to see CV syllables

Babbling (6+ months)

• Canonical (6): CV

• Reduplicated babbling (6-9): CVCV syllable chains (e.g., "dada")

• Variegated babbling (9-12): CV chains (with variations in C's and V's)

Illocutionary Period (9–12 months)

Intentional communication

Emergence of Speech Patterns (9+ months)

• Jargon: longer strings of variegated babbling

• Babbling is accompanied by sentence-like intonation patterns

• Phonetically Consistent Forms (PCFs)

Expressive Vocabulary Milestones

Age	Approximate vocabulary
12 months	1–3 words
15 months	10 words
18 months	50 words
24 months	200 words
30 months	450 words
36 months	1,000 words

Birth - 3 months

Receptive Milestones

• Reacts to loud sounds

• Smiles to familiar voices

• Quiets to familiar speakers

Expressive Milestones

• Cries for basic needs

• Begins to smile at familiar people

• Begins to make cooing sounds

4-6 months

Receptive Milestones

• Recognizes changes in vocal tone

• Eyes move toward sounds (sound localization)

• Responds to toys with noise

Expressive Milestones

• Vocal play

• Sounds for various emotions

• Begins to laugh

• Canonical babbling [6 months]: CV

7-12 months

Receptive Milestones

• Recognizes and turns to name [6-9]

• Comprehension of simple words & directions at 12

• joint attention

• Plays games, listens to songs

Expressive Milestones

• Shows objects by pointing

• Begins to use gestures (e.g., waving)

• First words emerge (around 12 months)

• Reduplicated babbling [6-9 months]: CVCVCV

• Variegated babbling [9-10 months]: badagu

1-2 years

Receptive Milestones

• Follows simple 1-step directions

• Understands simple questions

• Points to objects/pictures named & body parts (18 months)

Expressive Milestones

• Begins to put two words together

• Asks simple questions

• 50 words —> vocab spurt @ 2

• more milk —> 18-24 months

SYMBOLIC PLAY child uses objects to represent something else

2-3 years

Receptive Milestones

• Follows 2-step directions

• Simple opposites (e.g., big vs. small)

• Easily comprehends new words

Expressive Milestones

• Begins to put three words together

• Asks "Why?" - responds to what and where

• Simple prepositions (e.g., in, on)

3-4 years

Receptive Milestones

• Simple concepts (e.g., colors, shapes)

• Responds to name (from other room)

• Understands family words (e.g., sister)

Expressive Milestones

• Puts up to four words together

• Asks "When?" and "Why?"

• Simple pronouns and some plurals (-s)

4-5 years

Receptive Milestones

• Understands order words (e.g., first)

• Understands time words (e.g., today)

• Follows longer multi-step directions

Expressive Milestones

• Tells short stories, holds conversations

• Code switches (based on listener, place)

• Naming of letters, numbers

Brown's Stage I

12–26 months:

About 50 words;

basic phrases with communicative intent. (more juice, my doll)

MLU: 1.0–2.0.

Browns stage II

27–30 months:

Present progressive -ing, "in" and "on," regular plural -s.

• Man running, in house, on book, my kids

MLU: 2.0–2.5.

Brown's Stage III

31–34 months:

Irregular past tense, possessive 's, uncontractible copula.

• me drew, daddy’s hat, he is sick

MLU: 2.5–3.0.

Brown's Stage IV -

35–40 months:

Articles (a, the), regular past tense, third-person regular present tense.

• the bucket, a drink, she shopped, he runs

MLU: 3.0–3.75.

Brown's Stage V

41–46+ months:

Third-person irregular, uncontractible auxiliary, contractible copula, contractible auxiliary.

• doggy does tricks, he was jumping, she’s happy, she’s dancing

MLU: 3.75–4.5.

MLU (Mean Length of Utterance):

Average number of morphemes per utterance. Formula: Total number of morphemes ÷ Total number of utterances.

47+ months

MLU: 4.5+.

Copula

• UNCONTRACTABLE - llinking verb that cannot be shortened (at end of phrase)

• CONTRACTIBLE - linking verb that can be shortened (she’s happy)

Auxiliary

UNCONTRACTIBLE - helping verb that cannot be shortened (Yes, he is running)

CONTRACTIBLE - helping verb that can be shortened (she’s dancing)