Why Sheep and Fish Don't Add 'S' for Plural

Khan Academy

In this engaging grammar lesson, the narrator introduces the concept of "base plurals," a specific type of irregular plural noun where the singular and plural forms are identical. Using the classic example of "sheep," the video illustrates how standard pluralization rules (adding an "s") do not apply to this unique class of words. The narrator demonstrates that instead of changing the noun, we rely on context clues—specifically subject-verb agreement—to determine whether the subject is singular or plural. The video expands beyond sheep to explore other common base plurals like "fish" and "bison," showing how verbs change (e.g., "migrate" vs. "migrates") to indicate number while the noun remains static. A key segment addresses the nuanced exception of the word "fishes," clarifying that while "fish" is the standard plural for a group of individual fish, "fishes" is technically correct only when referring to multiple distinct species, a distinction often used in scientific contexts. For educators, this video is an excellent resource for teaching upper elementary and middle school students about the complexities of English pluralization. It moves beyond simple memorization by encouraging students to look at sentence structure and verb conjugation to understand meaning. The clear visual examples and the specific "fish vs. fishes" distinction make it particularly useful for bridging grammar instruction with scientific writing standards.