DuoCards - Vocabulary Builder

Contains adsIn-app purchases
57.5K reviews
Content rating
PEGI 3
5M+
Downloads
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About this app

Build vocabulary and learn languages with DuoCards, a flexible vocabulary builder for English and 50+ languages. Save new words from videos, articles, subtitles, courses, then practice with AI flashcards, speaking exercises, listening practice, and spaced repetition so the words stay in memory.

DuoCards is built for learners who want more than generic language lessons. You can discover useful words in real content, save them into a personal vocabulary deck, and review them with smart language flashcards that adapt to your progress.

What you can do with DuoCards:

- Build English vocabulary with flashcards that repeat at the right time
- Learn words from videos, subtitles, articles, courses, and shared decks
- Practice conversations with an AI language tutor for daily situations
- Improve pronunciation with speaking and listening exercises
- Save phrases, example sentences, and translations in one vocabulary app
- Study Spanish, French, German, Japanese, Korean, Italian, Portuguese, Russian, and more
- Create private decks or learn from public vocabulary sets made by other learners
- Use offline learning when you want to review without a stable connection

Learn from videos and articles

Language learning works better when words appear in context. DuoCards lets you save vocabulary from videos with subtitles and from foreign language articles, so you can connect each word with a real sentence, topic, and memory. Tap a word, check the translation, save it to your deck, and review it later.

Practice with AI flashcards

DuoCards combines classic flashcards with AI practice. Review words, listen to pronunciation, speak your answers, ask for examples, and practice short conversations. Use the AI tutor to understand grammar, see words in context, and turn your saved vocabulary into useful phrases.

A vocabulary builder for many goals

Use DuoCards as an English vocabulary app, a Spanish flashcards app, a language flashcards app, or a daily vocabulary builder for school, travel, work, exams, and everyday conversations. You can learn beginner words, advanced phrases, useful verbs, pronunciation, listening, and sentence patterns.

How DuoCards works:

1. Choose the language you want to learn.
2. Find useful words in videos, articles, courses, decks, or your own notes.
3. Save words and phrases to your personal vocabulary deck.
4. Practice with flashcards, AI conversations, pronunciation, and listening.
5. Review with spaced repetition until the words become familiar.

Why learners use DuoCards:

- Real content: learn from videos, articles, and examples instead of isolated word lists
- Smart review: spaced repetition helps you remember vocabulary for longer
- AI practice: turn saved words into conversations, stories, and grammar examples
- Flexible decks: create your own word lists or study public language sets
- Many languages: learn English and 50+ languages from one app
- Clear progress: see which words are new, known, or ready to review
- Offline review: keep practicing vocabulary while traveling or commuting

DuoCards is useful if you are learning English, improving Spanish vocabulary, studying French words, reviewing German phrases, practicing Japanese or Korean, or building a personal word bank in another language. It works for beginners who need simple vocabulary and for advanced learners who want to remember words from real content.

Use DuoCards for:

- English vocabulary and pronunciation practice
- Spanish, French, German, Italian, Portuguese, Russian, Japanese, and Korean words
- Language flashcards with spaced repetition
- AI tutor practice for speaking and grammar
- Video lessons, subtitles, and article-based learning
- Personal word lists, shared decks, and ready-made courses
- Daily review sessions for school, travel, work, or conversation

Download DuoCards and build vocabulary from real content. Learn languages with AI flashcards, video lessons, articles, speaking practice, listening exercises every day.
Build vocabulary with AI flashcards and video lessons
Updated on
Aug 31, 2026

Data safety

Safety starts with understanding how developers collect and share your data. Data privacy and security practices may vary based on your use, region, and age. The developer provided this information and may update it over time.
  • This app may share these data types with third parties
    App activity
  • This app may collect these data types
    Personal info, Financial info and 3 others
  • Data is encrypted in transit
  • You can request that data be deleted

Ratings and reviews

55.5K reviews
Amiran G
July 16, 2023
It's so horrible to give this app a try due to the frequency of ads being shown. The app is almost unusable when you just want to trial the free version. This is because every single adjustment of a word selection counts as an "action," with about 10 actions triggering an ad, even if you don't add the selection to your card deck. An ad was shown to me at least once every 10 seconds or so because of this.
115 people found this review helpful
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Marcin Urban
March 22, 2026
Looks like the app is still on development. If someone doesn't know basics in Norwegian there is a lot of mistakes with translation, norwegian words etc.. Sometimes I have to check it with explanation and then change translation of the word or even use different app to correct. App has potential but for now you must be careful with learning...
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DuoCards
March 25, 2026
Hi Marcin, we understand accuracy is important. While language models are constantly improving, occasional errors can occur. We encourage users to verify translations, especially for critical terms.
Martine Samhain
September 25, 2024
I had really hoped I could just build my Japanese vocabulary with this one. But nope. You have to learn hiragana signs first... Like everywhere else... That's pretty unnecessary unless you plan on moving to Japan. I'm just going on holiday and wanna learn to say a few things... Such a shame. App seemed nice otherwise...
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DuoCards
October 10, 2024
Hi Jack, there are courses of hiragana and katakana but you do not need to go through those. There are also other courses where romaji is always present on the card, so you don't need to know hiragana to learn. If you have trouble finding it, please contact us at info@duocards.com, and we will advise you. Michaela from DuoCards

What’s new

Learn more wherever you are with reliable offline study and syncing. Create personalized card sets with AI, get detailed pronunciation feedback, and practice with richer roleplays and comprehension exercises. We also added language-level progress, mobile deck export, and easier set search—plus many fixes and performance improvements.