Which developmental milestone is typically expected in infants by six months of age?

By six months of age, infants are typically expected to demonstrate the ability to babble and produce verbal sounds. This milestone reflects critical aspects of language development and social interaction. During this stage, infants experiment with their vocalizations, combining consonant and vowel sounds, which lays the groundwork for later speech. Babbling indicates not only the development of vocal skills but also cognitive growth and engagement with caregivers, as infants respond to interactions through sound.

In contrast, milestones such as walking independently, stacking blocks, and running are associated with more advanced motor skills that typically emerge later in a child's development. Walking independently usually occurs between 12 to 15 months, stacking blocks generally develops closer to 15 to 18 months, and running is expected around 18 to 24 months. Thus, babbling stands out as the appropriate milestone for infants around the six-month mark.