Babbling: consonant and vowel combos appear in chains (m, b, w, th), less nasal sound^6,14

Varying cooing sounds^6,14

Turns head toward source of sound¹⁶

Imitates several tones¹⁴

Voice quality normalizing, strong steady cry¹⁴

Vocalizes moods of pleasure up to 30 minute: chortles, squeals, gurgles, giggles, grins, laughs aloud¹⁴