The term ShopTalk comes from the expression “Talkin’ shop,” which refers to people who use specific vocabularies to talk about some field which the uninitiated may not understand. This is not necessarily a bad thing – for the sake of convenience, simplicity, or cognitive elegance (whatever that means) it can make a lot of sense to use the right words in the right situation. As stated on PainfulTalk, it’s really hard to talk about Wikipedia:Quarks when you have to explain what a quark is every time.

It is, however, impolite to employ ShopTalk in conversations when there are people participating who don’t know the terms. It’s a good way to make someone feel either left out or dumb. ShopTalk can also create a barrier for those who wish to study something new – if one picks up an advanced (graduate level) book on almost any topic that s/he is unacquainted with, it’s going to seem like another language.