The purpose of this study is to understand the nature of sentence meaning and to devise a plan to apply the study of sentence meaning to linguistic education. For this purpose, we first reaffirm the simple truth that the meaning of a sentence is the state of affairs to which the sentence refers, to the question of what the meaning of a sentence should be.
Then, as a methodology to study the meaning of Korean sentences, we present some explanation about the principle of compositionality and examples about how the principle of compositionality should be applied to the analysis of the meaning of Korean sentences. Although, in the meaning of sentences, there are parts to which the principle of compositionality can be applied, however, there are parts to which it is not. Therefore, we need to understand not only the generative aspects of sentence meaning, but also the context-dependent aspects.
Although these examples are often presented as counterexamples to the principle of compositionality, they are not counterexamples but examples that complement the principle of compositionality. In this study, three cases were presented. They are contextual dependency in the semantic analysis of noun phrases, understanding of unitity of idioms, specific constructions and elliptical constructions in compositional constructions, and distinction from implicatures. Just as a sentence syntactically has generative aspects and conventionally frozen aspects, there are parts in the meaning of a sentence that can be understood by operations, and there are parts that are subject to operations and cannot be analyzed any more. Applying the results of the study in sentential semantics to language education is to understand the cases in which the sentences are used step by step as the language learner progresses from the sentence type that results in the smallest operation to the sentence type that results in more complex operations. It may start with the hypothesis that it would be useful to present tasks and have them practice them so that they can acquire the ability to use sentences. This is because expanding the ability to use language from simple and objective sentences to complex and subjective sentences will surely serve the purpose of communication to communicate thoughts.