The eight parts of speech are the basic building blocks of the English language. They are:

1. Noun: A noun is a word that refers to a person, place, thing, or idea. Examples: dog, city, love, book.
2. Pronoun: A pronoun is a word that is used in place of a noun to avoid repetition. Examples: he, she, they, it.
3. Verb: A verb is a word that expresses action, occurrence, or state of being. Examples: run, eat, think, is.
4. Adjective: An adjective is a word that modifies a noun or pronoun by describing or giving more information about it. Examples: happy, blue, big, delicious.
5. Adverb: An adverb is a word that modifies a verb, adjective, or another adverb by adding information about how, when, where, or to what extent something is done. Examples: quickly, often, here, very.
6. Preposition: A preposition is a word that shows the relationship between a noun or pronoun and other words in a sentence. Examples: in, on, at, with.
7. Conjunction: A conjunction is a word that connects words, phrases, or clauses. Examples: and, but, or, so.
8. Interjection: An interjection is a word or phrase that expresses strong emotion or feeling. Examples: oh, wow, hey, ouch.

By understanding these eight parts of speech and their functions, you can improve your grammar and communication skills in English.