By 6 months

  • Responds to changes in others' tone of voice
  • Moves eyes towards noises
  • Produces different cries for varying needs (i.e. wet diaper versus hungry)
  • Babbles speech-like sounds, such as "ba", "pa", "mi"

By 1 year

  • Turns head and looks in the direction of noises heard
  • Responds when name is called
  • Recognizes the words for familiar objects and people 
  • Responds to simple commands (i.e. "no", "come here")
  • Engages in turn-taking activity (such as "peekaboo")
  • Uses gestures for a function (i.e. waving, shaking head "yes"/"no", raising hands to be picked up)
  • Says 1-2 words at a time ("mama", "dada", "hi"). Words may not be fully intelligible.

By 2 years

  • Points to body parts
  • Follows simple 1-step directions (i.e. "throw the ball")
  • Points to pictures in books when named
  • Begins to name pictures 
  • Puts 2 words together (i.e. "Mommy up", "More juice")
  • Uses the sounds /p, b, m, h, w/ in words

By 3 years

  • Understands opposites (i.e. "big" vs. little")
  • Follows 2-step directions
  • Names familiar objects, actions, and people
  • Talks when playing (i.e. says "moo" and "baa" when playing with animals)
  • Uses words for spatial concepts ("in", "on", "under")
  • Uses 3 word utterances for functional purposes (requesting, commenting, etc.)
  • Uses the sounds /k, g, f, t, d, n/ in words

By 4 years

  • Responds when name is called from other room
  • Understands words for colors and shapes
  • Answers simple "wh" questions ("what", "who", "where", "when", "how")
  • Uses pronouns
  • Uses plurals
  • Produces 4 word utterances
  • Discusses what happened during the day

By 5 years

  • Understands "time" and "order" words ("today", "tomorrow", "first", "last")
  • Follows multistep directions
  • Understands most of what is said, both at home and at school
  • Names letters and numbers
  • Uses sounds /l, s, r, v, z, j, ch, sh, th/ 
  • Holds topic of conversation
  • Tells a short story