Phrasal Semantics: the Principle of Compositionality

Phrasal Semantics: the study of phrases

Unlike the words, sentences cannot be memorized. The main reason why we cannot memorize the sentences is the creativity of the language. We can observe that there are a variety of ways of telling about a situation. For instance, there is no single sentence used to talk about a problem or express a feeling. There are variations in the word selection and combination of the selected words. The creativity of language enables humans to produce various phrases consisting of language's smaller units. According to the Rule of Compositionality, by looking at the smaller units' semantic features, such as words, in a sentence, we conclude the meaning of the bigger unit. Apart from the semantic features that give sense to the word, we also look at how these words are connected; in other words, the relation between the words. 

The Principle of Compositionality

The Principle of Compositionality is a rule that explains how we compute the meaning of sentences. According to this principle, as we have discussed, the meaning of a sentence is based on the meaning of its words and the way these words are connected. Now, let's understand what the principle tries to tell us with an example sentence.

The first rule of the Principle of Compositionality is that we compute the sentences' meaning based on the smaller units' sense. When we look at our example, "Justin loves tea.", it is apparent that there are three small meaningful units, which are Justin, loves, and tea.  The meaningful units are the parts, meanings of which we can easily comprehend. Let's write "M" and number them to indicate that they are meaningful. So, our list should be like Justin=M1, love=M2, tea=M3.

Having found the meaningful units in the sentence, we can continue with the second fact of the Principle of Compositionality. It says that the relationship between the words; in other words, how these words are connected in a sentence plays a crucial role in computing the phrases' meaning. Let's try to implement the second principle of the theory together.

In our example sentence, we need to establish a connection between the words. We can say that Justin is a subject, love is a verb, and tea is an object. In this sentence, the subject connects to a verb phrase. Briefly, the verb love and the noun tea merge. As a result, a new meaningful unit, which is a verb phrase, (M4) shows up. In the end, [Justin] (M1) is connected to the verb phrase [loves tea] and shapes the meaning of the sentence.

To sum up the Principle of Compositionality’s facts:

1. We compute the phrases based on the meanings of its smaller units: words.
2.       We compute the meaning of the phrases based on the way words are combined.