Sure, if you have the time. It is good to switch gears into the other language. It is hard to study one thing all the time. I recommend 2 dissimilar languages to avoid confusion. If you learn Spanish and Italian at the same time it can be confusing because of the similarities. Mandarin and Spanish would not have this problem.

I believe anything is possible with the right amount of time and effort. However, learning multiple languages requires an extensive amount of patience, time, and energy. Besides this, it is really easy to confuse words, phrases, and grammar from different languages when you are trying to learn them at the same time. I would recommend learning one language at a time to avoid the confusion and to make sure you can actually become fluent in one! After you become fluent in one language, it'll make learning another language you want easier :)