The preposition commonly used before "the matter" in English is "of." This construction is used to introduce the subject or topic being discussed. For example, "The matter of climate change is a significant concern." The use of "of" in this context is supported by linguistic conventions and is widely recognized in both formal and informal writing.

The preference for "of" before "the matter" can be attributed to its function in specifying the subject or topic. In English, prepositions like "of" are often used to indicate relationships between nouns, and in the case of "the matter," it signifies the subject or issue at hand. This usage is consistent with the broader function of prepositions in English, which is to establish connections between words and phrases.

Data from the Corpus of Contemporary American English (COCA) supports the prevalence of "of" before "the matter." In a search of the COCA database, "the matter of" appears significantly more frequently than other prepositions in similar contexts. This indicates that "of" is the dominant choice in contemporary American English.

For instance, the COCA search reveals that "the matter of" is used in a variety of contexts, such as legal, political, and social discussions. This widespread usage further underscores the standardization of "of" before "the matter" in English. The consistency of this construction across different registers and contexts demonstrates its acceptance and utility in the language.