Mercury in Capricorn knows how to spot potential problems and wants to correct it before it becomes a problem. This sign placement is all about preparation. This is why Mercury in Capricorn likes to plan out actions, considering everything that can go wrong, before they choose to take steps forward.
Mercury in Capricorn is careful in their communication style. They like to think through what they say before they say it. Mercury in Capricorn understands the importance of words and wants to choose the best words possible.
Mercury in Capricorn is careful in the words they choose to say to other people. Many stick their foots in their mouth when they are younger, so as Mercury in Capricorn grows older, they learn to speak more slowly as to not say something they should not say to people.
When a Mercury in Capricorn is upset with someone, it can be hard to get a response out of them. They will shut down and analyze what they are upset about, trying to come up with a solution for how to fix it.