Here's why:
* Language names are generally not capitalized in English. There are exceptions, like proper nouns (e.g., French, Spanish), but "English" is not one of them.
* Consistency: Keep your resume formatting consistent. If you're capitalizing "English," you might feel compelled to capitalize other language skills as well, which isn't the standard practice.
Example:
Instead of: "English (Native), Spanish (Fluent)"
Write: "English (Native), Spanish (Fluent)"