Oh okay, so it's something that vets and doctors use! I see.
It's a shot that prevents diseases.
What is a vaccine?
Good, and yours?
Should I tell him about how my cat got vaccinated over the weekend? Hmm, probably not, I don't think he would be interested. He looks busy.
How was your weekend?
At this stage, we can see the child has the ability to learn a new word and the concept represented by it, as well as its phonological form. She is encoding the contextual conditions at the initial exposure to this new word. This stage builds on the previous stage, syntactic development, because there, she learned how to use her newly-acquired words [in her lexicon] in proper sentences.
At this stage of development, you can see that the child has a good grasp of social cues. She notes the paralinguistic cue of his uninterested facial expression, and decides to not pursue certain conversational topics based on that observation. She notes an extralinguistic cue that he is at work and probably doesn't have time to go into depth about a topic, so she just keeps the conversation at a small talk level. Linguistic cues are used to take conversational turns. This stage builds on the previous stage by utilizing her lexicon to communicate, but doing so in socially appropriate ways.