Resources for language learning and retention that I've used
English is my native language, but from a young age I've been obsessed with other languages, how they work, their sounds, their grammar, etc. I speak Spanish, French and Mandarin, and I'm currently working on Arabic and Basque.
​Here are a few tips and tools that have served me well in keeping up my languages whilst learning new ones. As a certified CELTA teacher I’ve also included some English learning and ESL teaching resources.
What I love about making a goal to learn a language is that you'll technically never achieve it- you never actually finish learning the langauge. Languages constantly change and so do you, so you are constantly learning and relearning everything. Fluency (in my opinion) just means you’ve reached a level where you can function well in that language- it doesn’t mean you have perfect speech or never make grammar mistakes, (there is a difference between fluency and accuracy) and it definitely requires you to be open to any changes and adaptations that the language experiences. :) 
A few tips:
  • Listen to music (even though you may not understand it yet)
  • Find others who are learning as well and practice
  • Watch movies/shows in the target language- for example C-dramas or Telenovelas (Yes, the'll make you cringe...but they'll help your listening comprehension abilities)
  • Read, Read, Read! This can really help you maintain a language once you've reached a higher level.
English Teaching Resources:
Other language learning links and polyglot/travel blogs that I've found helpful:​ 
  • https://www.fluentin3months.com/
  • http://travelacorn.com/
  • Duolingo.com (this can help you start a language) 
  • ChinesePod
  • Pleco App & Chinese Trainer App (both Chinese dictionary/writing apps)
  • Chinese Zero to Hero
  • WordReference (instead of Google Translate)
  • The ASL App
  • Ikasten (online courses in Basque)
  • Alif Baa Books for Arabic learning
(Disclaimer: I've just found these helpful, no one is paying me to share these)