In these early months, babies focus on sound perception and pre-linguistic communication. They learn to distinguish speech sounds and develop the vocal apparatus needed for future speech.

Crying: The primary form of communication from birth, indicating hunger, discomfort, or a need for attention.

Cooing: Soft, vowel-like sounds ("ooo," "aaa") that emerge around 2–4 months as an early form of vocal play.

Differentiated Cries: Parents often learn to distinguish cries for hunger, pain, or tiredness.

Responding to Sounds: Infants turn their heads toward sounds and may startle at loud noises.

Smiling: Social smiles emerge in response to a friendly face or voice.