I can be both, at different times. As an adult, I know what to say in most of the most common, scripted conversations, such as greetings, saying goodbye, etc. But still manage to sound socially awkward, because it's not accompanied by the right facial expression or body language.
At times I'm talkative and tend to go on about things too much, or in too much detail. I don't really do small talk, in the sense that it doesn't have the same social function for me as it does for most people. If I talk about the weather, I talk about the weather. I monologue, for ages. When the small talk requirement is usually a shrt answer. If someone mentions parking difficulties to me, I launch into a speech about the difficulties in my area, which will extend to how crowded and congested cites are, and how impractical it is to have a big car, how people have cars to boost their ego and social status, but don't really need them, how people should use public transport more, but then that gets crowded too and I hate that, but at least it reduces CO2 emission, etc. Or I over-explain and say the same thing over and over again.
At other times, I shut down and don't speak at all. I do this in group conversations, I have many difficulties participating in group social situations or discussions. Difficulties with the subject matter not interesting me and not having anything to say/contribute, not being able to follow or respond to banter, not being able to process the conversation in time to be able to respond, so when I have thought of something to say, the conversation has moved on, someone else is speaking and the moment is gone. When I sepak, people ignoring me and then someone else starts speaking and they listen to the other person instead of me. I feel that I don't have a voice.
When people speak, they aren't just speaking, they actually exchanging emotimemes, little packets of emotional messages consisting of both verbal and non-verbal information, that the other person receives and then responds to. When I talk, I only exchange verbal information, I don't really know how to exchange emotimemes. They get lost in translation, or I receive them, and don't know how to respond, so do nothing, which is then interpreted as indifference.