Which aspect of language focuses on the arrangement of words in sentences?

The correct choice focuses on syntax, which is the aspect of language that involves the rules and principles that govern the structure of sentences. Syntax determines how words are combined to form phrases and sentences, effectively shaping the grammatical relationships between words. This is crucial for creating meaningful communication, as different arrangements of the same words can alter meaning entirely.

For instance, the sentences "The cat chased the mouse" and "The mouse chased the cat" contain the same words but convey different meanings due to their syntactic structure. A solid understanding of syntax allows ESL learners to grasp how sentences are formed in English, which is foundational for both writing and comprehension.

Other aspects of language, such as phonology, focus on sounds; morphology deals with the structure and formation of words; and semantics pertains to meaning. While all these aspects play important roles in language use, it is syntax that specifically addresses how words are systematically arranged in sentences.