Should I include a paper published in a non English language in my CV?

If you have published a paper, you should include it in your CV. It does not matter what language the paper is in.

For the aid of people who do not speak the language, however, you may wish to include a translation of the paper title as a note, e.g.,:

J. Caesar, Commentarii de Bello Gallico [Commentaries on the Gallic war], Caesar House Press, 49 BC, (in Latin)

Of course you should. It is well known that the best journals are in English but there are others that can be not bad and they are not necessarily written in English. In South America there are a couple of journals that are not on the top ten, but maybe on the second quartile and they have articles both in English and Spanish. Also, you worked on that paper so this may not add a lot to your cv but it is better than nothing! :)