What developmental milestone typically occurs around 18 months of age?

The milestone of vocabulary explosion and rapid word learning around 18 months is a significant aspect of language development in children. At this age, toddlers typically experience a dramatic increase in their vocabulary, commonly referred to as a "vocabulary explosion." This occurs as they begin to make connections between objects, actions, and their corresponding words, resulting in the rapid acquisition of new terms.

By 18 months, many children can produce around 10 to 50 words, which may mainly include names of familiar people, objects, and simple verbs. This process is crucial as it sets the foundation for further language skills and cognitive development. The ability to communicate more effectively allows them to express their needs, thoughts, and feelings, facilitating social interaction and relationships.

In contrast to the other options, the understanding of complex sentences typically develops later, vocabulary mastery at this age is still emerging, and writing simple words is a skill that usually comes much later in development. Thus, the emphasis on vocabulary growth as a hallmark of around 18 months highlights the importance of this period in the language acquisition process.