This study is about the understanding between people that follows certain rules to create an interaction. Meaning of phrases don’t need to be stated, but they are always implied. This study shows how words can be interpreted in different ways based on the context of the situation. In certain situations, words can have a certain meaning, since they don’t need to have a specifically defined meaning all of the time.
Syntaxis

Is the study of how words are combined with others to create sentences and in what order this can be done, and also of how sentences can be structured.

 Semantics

It’s about the interpretation and the meaning of words and also sentence structure. It refers to the branch of study of linguistics that deals with language and how we interpret meaning. It also focuses on the difference between figurative and literal meaning.
Regularity

Refers to the ease that people who belong to a social group and have had similar linguistic experiences, have to understand each other by sharing non-linguistic knowledge.