A word or phrase (or several) that becomes defining characteristics of a person's speech. It can either denote a particular geographic upbringing, is in y'all or ayeah or it can be more particular to an individual or group like family slang. For example, a friend of mine when faced with someone else's tragedies, will routinely say, "It gets hard." I have been accused of having ohmigod as my key phrase but I am trying to wean myself of it and am looking for a new one.