Knowing a second language can make you more employable and a better traveler, not to mention provide you with a whole new set of creative (and unintelligible) swear words to use when you accidentally bang your head on a cabinet door.

But hanging on to your high school or college Spanish—or French, or German, etc—is a challenge once you're no longer enrolled in classes. Fortunately, with a little effort, you can stay literate in your language of choice—or even learn a new one.

1. GO MOBILE.

They're not quite as addictive as Candy Crush, but language learning apps are a perfect, productive way to kill time. And because there are so many of them, you can shop around to find one that jives best with your preferred learning style.

If you're not sure where to start, consider one of these highly rated standouts: Memrise was founded by an expert in mnemonic techniques, and is designed to not just teach a language, but to cement it in your memory. This makes it a great choice if you need to improve your vocabulary.

Or try Duolingo, which takes an entertaining and holistic approach to learning a language; it teaches not only reading and writing but listening and speaking (i.e. it's a perfect travel tool).

2. FIND A CONVERSATION PARTNER, OR SEVERAL.

Join a local Meetup group to connect and chat with fellow students of your desired language, and get in some regular conversational practice. Or, find a virtual convo partner on a site like Conversation Exchange or the Exchanging Languages subreddit; native speakers of other languages who want to practice their English will be happy to trade small talk with you over Skype.

3. READ, WATCH, LISTEN.

If you're reasonably literate in your language of choice, consider picking up a favorite children's or YA book (or audiobook) in translation. Harry Potter, for example, is available in 68 different languages. And next time you're Netflix-binging, browse for foreign films that you can watch with English subtitles, or re-watch a favorite show with overdubbed audio in one of the service's 15 available languages.

4. TAKE THE TRADITIONAL APPROACH.

Language classes are an investment in terms of both time and money, but they remain an effective way to learn, and especially to practice speaking, a language with some expert guidance. Community colleges or continuing education programs offer a variety of language classes, including ones with a fun focus on literature, film, or even food. And depending on where you live and what you want to study, you may be able to link up with a center like the French Institute Alliance Francaise, which offers not just classes but community and cultural events where you can practice chatting.