Babies less than 1 month old:

• Listen to the rhythm and melodies of speech.
• Usually can pick out their mother's voice.
• Learn the rhythm and melodies of two languages when both are frequently spoken in their environment.

• Use undifferentiated crying, which is crying that sounds the same and does not vary by specific need.

1- to 4-month-old babies:

• As early as 1 month, may recognize the basic and distinct sounds of a language (phonemes), such as "tr" and "cl."
• Prefer "baby talk" and voices with high pitch.
• Become alert to sounds by blinking or widening eyes; may start to be awakened by noise, become startled, or turn toward a sound to look for its source.
• Will quiet to their mother's voice.

• Make cooing sounds, often vowel sounds such as "ah-ah-ah" or "ooh-ooh-ooh."
• At about 3 months, make cooing sounds back to someone who is talking to them.

5- to 6-month-olds:

• Recognize their own name.

• Make sounds like "goo" and blow bubbles at the same time.
• At about 6 months, start to babble, repeat sounds, such as "ma-ma-ma" or "bah-bah-bah" to get attention or express feeling.
• By 6 months of age, vary their cries to signal specific needs.

7- to 9-month-olds:

• Hear words as distinct sounds.
• By 9 months, usually recognize the meaning of some facial expressions and tone of voice, such as when a parent says "No!"

• Repeat sounds that they hear.
• Mimic the rhythm of the way others talk to them.
• May say words like "mama" and "dada."
• By 9 months may wave "bye-bye" when prompted.

10-month-olds:

• Usually understand "mama" and "dada" and can identify each parent.

• Correctly refer to each parent as "mama" or "dada."