Social duplication.

[Agnes]

Social duplication is when you talk to someone frequently enough that you start using the same terms and mannerisms as them. Usually spotted in [close friends] and [intimate] relationships, both or either of the parties in frequent contact take words and phrases, among other forms of [communication] and apply it in their conversations. Often, this can have a chain effect, having the people that they talk to also display the passed on mannerisms.