In the phrase "I learned that song in kindergarten," what part of speech is "I"?

In the phrase "I learned that song in kindergarten," "I" serves as a pronoun, specifically a personal pronoun. Pronouns are words used to replace nouns and can refer to people, places, or things. In this sentence, "I" stands for the speaker or the person performing the action of learning.

This usage of "I" demonstrates the pronoun's function of identifying the subject of the verb "learned." Personal pronouns like "I" help avoid repetition and make sentences clearer by representing known or understood entities. In contrast, other parts of speech, such as adjectives, nouns, and adverbs, serve different roles in a sentence, but "I" specifically fulfills the role of a subject pronoun here.