Hi Rena! You asked a really great question and I have to say that my answer has probably evolved over time. I grew up with two mother tongues, English and Hakka Chinese so, from a young age, I was immersed in a multilingual environment. I have been lucky to have maintained my Hakka ability, by speaking it with family often, despite living in an English-speaking environment most of the time. For languages I acquired at a later age like French, Mandarin, Cantonese and Japanese, I make a conscious effort to consume media in these languages. For example, reading French novels, watching C-dramas, listening to Japanese music etc. I am also very lucky to have lived and worked in France and Japan for a few years; while I was abroad, I would seek out opportunities to interact with locals, from grocery shopping to going out with friends. Much like Paul and Mehran have suggested already, finding a language exchange partner, international friends or teachers would be one of the most effective ways to keep using your target language(s). Other ideas to passively or actively maintain your secondary languages: - Writing journal entries in the target language(s) - Watching the news in the target language(s) - Texting international friends in their languages(s) - Narrating every day actions in the target language(s). This was a really fun question to think about! I hope my ramblings could be of some help and wish you the best of luck in your language journey :)