First of all, what is a part of speech? Grammarians have devised a system to sort every word in the English language into nine categories. We call those categories parts of speech.
The first part of speech is the noun. A noun is usually defined as a "person, place, or thing," but events, qualities, and abstract concepts are also nouns. There are many subcategories of noun, so many that we decided to make a separate article about them! The subject of a sentence is most often a noun.
The second part of speech is the verb. Verbs