Studying the practical use of signs and their impact on everyday life is called

Studying the practical use of signs and their effect on everyday life is called pragmatics.

Pragmatics concerns how signs work in real contexts of use and action.

Linguistics is the broad science of language, wider than sign use in daily life.

Syntactics studies the structural arrangement of signs, not their practical impact.

Semantics studies the meaning of signs, not their situated use.

Syntactics, semantics and pragmatics form the three divisions of semiotics.