PolyglotTrainer is a vocabulary trainer for polyglots: people who speak and want to maintain 4+ languages. Very simple and focussed on one goal: to learn the 1000 most common words of several languages in parallel.
You start by choosing your root language, which is either your mother tongue or a language you are very comfortable with. Then you choose the languages you want to learn, and also in which order you want them to appear. Then you can either just get words in random order for as long as you want, or you can choose to make a timed session. The timed session is not just a reference for you for how long you should stay focussed on learning. There is an algorithm behind that divides the time you choose into parts where first you get to learn new words, then words you saw before but didn’t know, then words you knew but still have to repeat, and finally those that you already repeated three times but have to refresh after one month. Whether a word will be saved as known or not depends on your manual feedback. You are doing this for yourself, so be honest with yourself.
You may encounter occasional mistakes. When you do, a little edit button allows you to submit the corrected version. This is a crowdsourcing element to ensure quality and help other users. AI creates the first draft, humans make the fine-tuning.
So far it supports the following languages: English, French, Portuguese, Spanish, German, Danish, Italian, Catalan, Esperanto, Greek, Czech, Polish, Ukrainian, Russian, Bahasa Indonesia, and Latin. More languages will be added on demand.