• coos and gurgles
• startled by loud sounds
• makes eye contact briefly

4 to 6 months

• babbling begins
• smiles in response to speech
• looks in response to name

7 to 9 months

• uses wide variety of sound combinations
• understands "no," "bye-bye," etc.
• shouts to attract attention

10 to 12 months

• uses consonants and vowels in vocal play
• closes mouth without drooling
• may acquire first true word
• will give block, toy, or object on request

18 months

• uses all vowels and consonants in jargon
• basically unintelligible with exception of a few words
• uses 3 to 20 words
• follows simple one-step commands
• says "all gone" and asks for "more"

2 years of age

• approximately 65% intelligible
• uses approximately 50 recognizable words
• comprehends approximately 300 words
• uses two word phrases
• refers to self by name

3 years of age

• approximately 80% intelligible
• uses 500 intelligible words
• comprehends approximately 900 words
• can ask simple questions
• listens to a 20 minute story

4 years of age

• becoming very intelligible in connected speech
• uses 1000 to 1500 words
• comprehends 1500 to 2000 words
• carries on long, detailed conversations
• combines 4 to 5 words in a sentence

5 years of age

• most consonant sounds used consistently and accurately
• combines 5 to 8 words in sentences
• classifies according to form, color or use
• tells long story accurately
• counts 10 objects