I read a book on introverts, what you have described is listed as one of the possible signs of an introverted style. We take longer to process and contemplate.

Extroverts recharge when around all the social activity and tend to blurt things out.

Just one theory, another way to look at things.

Once while talking to my college professor, he asked if I was a writer. He then explained that he has noticed that people who write often have a more deliberate mind that considers and reflects. We might be slower in conversation because of this.

( Introvert Advantage is the book I read on this, I got a copy through my public library, and here is their short quiz:

Please read the following statements and see if they sound like you. If they do, you are probably an Introvert. If they do not, then you are probably an Extrovert.

• I feel energized by time alone.

• At social events I lose energy as the event progresses.

• People think of me as calm and reserved.

• I have good eye contact when listening, but I may look away when talking.

• Unless I know the subject very well, I speak slowly and sometimes need to hunt for words.

• I often have delayed reactions.)