He said something like “you say > it this way when you really know the person and you’re saying that the other way when it’s more formal“, but I think really it was just a slangy way to mis-stress something and it didn’t have to do with familiar/formal or not.
There’s such a thing in Spanish and in French. Formal and informal settings is reflected in the language. French even distinguishes between three different level of vocabulary (one for very informal settings (close friends), one for business and daily interactions, and one for very formal settings. It’s all cultural.