<p>The best way to learn a language fluently is to go to that country. It takes a person 6 months to learn a language when forced. So if you were to go to Greece, and were forced to learn it, you will get it quick. Or try to hang out with people who fluently speak those languages and hang with them often.</p>
<p>Irish will be hard since not many people speak Irish, and not many Irish people even speak that. Based off of that list Dutch and Swedish will be the easiest, since its similar to English, from there do German. Learn Spanish then do Portuguese, from there do French. That will make French easier to learn. Russian, Chinese, and Japanese will be hard as hell though. Those are some quick shortcuts.</p>