How do word meanings and grammatical structure both contribute to sentence meaning?

In the study of semantics, the meaning of a sentence is understood to be composed of two distinct but integrated parts: the individual meanings of the words it contains and the structural or grammatical meaning conveyed by the sentence itself.1

Word Meanings

The meaning of a sentence is fundamentally rooted in the specific words chosen. For example, the sentences "the dog chased the cat" and "the boy chased the cat" differ in meaning because the lexical items dog and boy carry different meanings. In linguistic frameworks, such as transformational-generative grammar, these words are drawn from a lexicon that associates each word with specific syntactic, semantic, and phonological features.12

Structural Meaning

Grammatical structure provides the framework that organizes these words into a coherent message. The importance of structure is evident when comparing sentences that contain identical words but different arrangements, such as "the dog chased the cat" and "the cat chased the dog". In these cases, word order distinguishes the subject from the object, thereby altering the sentence's meaning.1

Beyond word order, languages utilize various formal resources to convey structural meaning, including:
* Word form: Changes in the shape of words to indicate grammatical roles.1
* Particles: Specific markers used to reinforce grammatical distinctions, such as subject or object markers.1
* Prosodic features: In speech, pitch, stress, and intonation are critical carriers of structural meaning, allowing speakers to highlight information or indicate attitudes.1

Ultimately, the compositionality of natural language dictates that the meaning of complex expressions is determined by and predictable from the meanings of their simpler constituents and the grammatical rules that combine them.3