* It's a proper noun: "French" in this context refers to the specific language, which is considered a proper noun. Proper nouns are always capitalized.
* Distinction from the adjective: Capitalizing "French" differentiates it from the adjective "french," which describes something originating from France (e.g., "french fries").
Examples:
* I'm taking a French class this semester.
* She's fluent in French.
* The French language is spoken in many countries.