The eight parts of speech are the basic categories of words in English grammar, each serving a distinct function in sentences:
1. **Nouns**: Words that name people, places, things, or ideas (e.g., dog, city, happiness).
2. **Pronouns**: Words that replace nouns to avoid repetition (e.g., he, she, it, they).
3. **Verbs**: Words that express actions, states, or occurrences (e.g., run, is, think).
4. **Adjectives**: Words that describe or modify nouns or pronouns (e.g., happy, blue, large).
5. **Adverbs**: Words that modify verbs, adjectives, or other adverbs, often indicating how, when, where, or to what extent (e.g., quickly, very, here).
6. **Prepositions**: Words that show relationships between nouns (or pronouns) and other words in a sentence, often indicating direction, place, or time (e.g., in, on, at, by).
7. **Conjunctions**: Words that connect words, phrases, or clauses (e.g., and, but, or, because).
8. **Interjections**: Words or phrases that express strong emotion or surprise, often standing alone (e.g., wow, oh, ouch).