Indeed... :P

There are a few grammatical issues in the description:

1. "We give you an Array of friend's list." (should say "We give you an array of friends.")

2. This method takes an array of friends name and return a greeting messages Array. (should say "This method takes an array of friends' names and returns a greeting messages Array.")

3. If the argument is a valide array of strings... (should say "If the argument is a valid array of strings...")

You'll have to know fundamentals to debug something, that's inherent. Since the kata is framed as solving an issue with existing code, and you are given how it should work vs. how it currently works, i'd say this is pretty solidly a Debugging kata.

My suggestion is to change the category from "fundamentals" to "bugfixing" for this kata. While it does touch on fundamentals, i think this belongs more in the "bugfixing" category.