What developmental milestone occurs around the end of the first year?

Around the end of the first year, a significant developmental milestone for infants is the expansion of vocabulary. During this stage, children typically begin to say their first meaningful words, which may include "mama" or "dada," and start to understand a few simple words and commands. This aligns with the cognitive and communicative advancements they are experiencing as they become more aware of their social environment and begin to engage more actively with those around them.

At this age, while there might be some recognition of sounds and structure, the ability to combine words typically does not emerge until they are closer to the age of two. Similarly, the ability to produce single sounds evolves earlier in their development but does not signify the same communicative achievement as the expansion of vocabulary. Narrative storytelling is a more complex skill that develops much later, as it requires the ability to organize thoughts and ideas coherently, something that is usually not seen until children are older, typically around preschool age. Thus, the expansion of vocabulary is a key milestone that signifies both language acquisition and cognitive development at the end of the first year.