Here's why:
* Old English Roots: These words, like "fish," "sheep," and "trout," have origins in Old English. Their plural forms were originally different from the singular, but over time, the language changed and the plural forms became the same as the singular.
* Historical Usage: The reason for the change is likely a combination of factors, including:
* Merging of Forms: The singular and plural forms might have been similar enough that they merged over time, especially in spoken language.
* Common Use: These words were commonly used for things that were counted in groups, so the singular form might have become more common in everyday speech.
Examples:
* Fish: The Old English plural was "fisc."
* Sheep: The Old English plural was "scēap."
* Trout: The Old English plural was "trūta."
Other Examples:
Many other words have irregular plural forms in English:
* Child - Children
* Woman - Women
* Goose - Geese
* Mouse - Mice
The fascinating thing about English is that it is a language that has evolved over centuries, and this evolution includes changing the way we form plurals!