What does morphology study in language?

Morphology is the study of how words are formed and structured in a language. It specifically focuses on the internal structure of words, including the ways that morphemes— the smallest units of meaning— combine to create meaningful words. This discipline examines various aspects such as prefixes, suffixes, and root words, which are the building blocks that can be manipulated to create new words or alter meaning.

In this context, the understanding of how words are constructed out of letters relates directly to morphology, as it encompasses the way letters form morphemes and how these morphemes combine to create complete words. Therefore, recognizing that morphology deals primarily with the construction and formation of words explains why this option is the correct response.

Other options focus on different areas of linguistics. The study of sounds pertains to phonetics, sentence structure is addressed by syntax, and understanding word meanings falls under semantics. While these elements are important in the broader study of language, they do not specifically address the focus of morphology on word construction.