Which branch of linguistics studies the formation of grammatical sentences?

The branch of linguistics that studies the formation of grammatical sentences is syntax. Syntax focuses on how words combine to form phrases and sentences, and it analyzes the rules and principles that govern sentence structure. Understanding syntax is crucial for grasping how different languages construct their grammatical frameworks, including word order and agreement between subjects and verbs. This study encompasses both the organization of individual sentences and the relationships between parts within those sentences, providing insights into the complexity and variety of sentence structures across different languages.