I do not mean to sound like a snob, but I thought I would point out the (apparently not so) obvious; English is a Germanic language. That explains the numerous amount of cognitives between the languages–including the word "Kognativ".
In my opinion, German should be the easiest language for a native English speaker to learn.
In the USA, it makes more sense to learn Spanish. Don't count German out, however; if you wish to go into international business, German is still a very useful language!
