Comparison

Polyidiom vs DejaVocab

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Polyidiom

Master idioms and slang across multiple languages with engaging illustrations and smart learning algorithms. Track your progress, save favorites, and explore cultural backgrounds. Offline access makes learning convenient anytime, anywhere.

Highlights
  • Card-based learning with definitions and history
  • Detailed explanations of cultural backgrounds
  • Save favorite idioms for review
  • Track learning progress and statistics
  • Support for six languages
  • Cartoon illustrations for enhanced memory
  • Offline learning support
Features
Read full description

PolyIdiom - Multi-Language Idiom Learning PolyIdiom is a multi-language idiom learning app designed for language learners. Through beautiful cartoon illustrations and smart learning algorithms, idiom learning becomes vivid and interesting. Supporting Chinese, English, Spanish, French, Japanese, and Korean, you can easily master cultural essences regardless of your native language. Core Features Card-based Learning: Flip-style learning experience with definitions, origin stories, and practical examples Detailed Explanations: Deep understanding of cultural backgrounds and usage scenarios Smart Favorites: Save your favorite idioms for review anytime Learning Statistics: Track progress and view learning achievements and trends Product Highlights Six Language Support: Complete coverage of Chinese, English, Spanish, French, Japanese, Korean Cartoon Illustration Design: Beautiful illustrations for each idiom to enhance memory Smart Learning Algorithm: Personalized content recommendations based on learning habits Elegant Interface Design: Clean and beautiful UI focused on learning experience Offline Learning Support: Learn anytime, anywhere without internet connection Subscription Service Free Version: Learn 3 idioms daily, 3 favorites limit, 1 language switch Premium Membership: Unlimited learning, unlimited favorites, switch languages anytime, ad-free experience Subscription Details Yearly Subscription: $7.99/year, average $0.67 per month Monthly Subscription: $1.99/month, flexible subscription Service Information Subscription auto-renews unless cancelled at least 24 hours before the current period ends Manage or cancel subscription in iPhone Settings > Apple ID > Subscriptions The current free trial period will be forfeited upon subscription activation Subscription fee charged to iTunes account upon purchase confirmation Terms of Service: https://polyidiom.app/terms-of-service Privacy Policy: https://polyidiom.app/privacy-policy Download PolyIdiom now and start your multi-language idiom learning journey!

About

DejaVocab

This app helps you learn languages by immersing you in real-world content like videos, podcasts, and books. It builds a personal language corpus by capturing and organizing language chunks from natural input, allowing you to review words within their original context. The system integrates spoken and written language for a continuous learning experience.

Highlights
  • Learn from videos, podcasts, and audiobooks
  • Build a personal language corpus
  • Review vocabulary in original context
  • Integrates spoken and written language
  • Supports EPUB, PDF, and text files
Features
Read full description

Deja 从一个问题开始: 语言,为什么总是被学成抽象的单词? 在真实世界中,语言来自视频、播客、阅读和声音。 Deja 将这些语境中的表达自动提取、组织,逐渐形成一个属于自己的语料系统。 复习不再是孤立的记忆,而是回到语言第一次出现的那个语境。 阅读、听力、学习不再分离,所有输入汇聚成一条连续的语言路径。 Deja 不属于某一种格式或平台,它试图构建的,是一个会随着使用不断生长的语言系统。 Deja starts with a simple idea: Language is not learned from isolated words, but from real usage. Import videos, podcasts, books, or any text. Deja automatically captures phrases in context and turns scattered exposure into a growing personal corpus. Review is not repetition. It is a return to the moment where the language first made sense. Reading, listening, and studying are no longer separated. Everything flows into one continuous system, one evolving memory. Deja is not about formats or platforms. It is about building a language system that grows with you. Contact WeChat: longhao1596 Discord Community: https://discord.gg/AC7sNMJW Privacy Policy: https://dejavocab.com/privacy-policy/ Subscription Information Subscriptions renew automatically 24 hours before the end of the current period You can manage or cancel your subscription in Apple ID settings at any time After cancellation, access remains until the end of the current subscription period Payment will be charged to your iTunes account upon confirmation of purchase Terms of Service: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Don’t let words slip past unnoticed. Let DejaVocab capture every meaningful chunk of language. Download DejaVocab and build your own language corpus.

Screenshots

Polyidiom4 screens
DejaVocab4 screens

Verdict

The call

The clearest difference is rating: Polyidiom at 5.0 against DejaVocab's 4.6. Polyidiom also leads on update cadence (every 3 days vs weekly) and review sentiment (100% vs 87%). DejaVocab's advantage is ratings volume (60 vs 1). On price, ads, in-app purchases and monetization model there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Polyidiom sells 3 in-app purchases, starting at $1.99 per month and DejaVocab sells 6 in-app purchases, starting at $5.99 per month. Whichever you choose, the download price is not the number that matters.

ReceptionRating · Positive reviews · Number of ratings

Polyidiom holds the better App Store score, 5.0 against 4.6. That said, the two scores are not equally well evidenced: DejaVocab has 60 ratings behind it against 1, so its average is the more settled of the two. Written reviews point the same way: 100% of Polyidiom's written reviews are positive against 87% of DejaVocab's.

UpkeepUpdate frequency

Polyidiom ships an update every 3 days, DejaVocab weekly. The most recent releases landed on October 8, 2026 and October 25, 2026 respectively.

Scorecard4 real differences · 6 level
Polyidiom versus DejaVocab: the parameters behind the verdict, then further details
ParameterPolyidiomDejaVocab
PriceFreeFree
Rating5.0 (1 ratings) — better4.6 (60 ratings)
Positive reviews100.0% of reviews — better86.6% of reviews
Number of ratings160 — better
Update frequencyEvery 3 days — betterWeekly
AdsNoNo
In-app purchasesYesYes
MonetizationFreemiumFreemium
DevicesiPhone, iPadiPhone, iPad
Requires iOS17.0 — better17.6
Further details — not scored
Size43 MB360 MB
Age rating4+17+
Developer亲强 吴灏 龙

Customer experience

Polyidiom

All ratings1 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews2 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

DejaVocab

All ratings59 ratings
Positive86.4%
Neutral1.7%
Negative11.9%
Written reviews67 reviews
Positive86.6%
Neutral4.5%
Negative9.0%

In-app purchases

3 purchases

Polyidiom

Subscriptions2
  • PolyIdiom Premium (Monthly)$1.991 Month
  • PolyIdiom Premium (Yearly)$7.991 Year
One-time1
  • Polyidiom Lifetime Membership$9.99
6 purchases

DejaVocab

Subscriptions4
  • DejaVocab 高级版3 Days trial$5.991 Month
  • DejaVocab 高级版3 Days trial$7.991 Month
  • DejaVocab 高级版年付7 Days trial$49.991 Year
Show 1 more
  • DejaVocab 专业版年付7 Days trial$69.991 Year
One-time2
  • DejaVocab 共建者$199.99
  • DejaVocab 共建者 Plus$299.99

Questions

Is Polyidiom free?
Polyidiom is free to download, with in-app purchases available.
Is DejaVocab free?
DejaVocab is free to download, with in-app purchases available.
Which has better reviews, Polyidiom or DejaVocab?
Polyidiom is rated higher. Polyidiom averages 5.0 out of 5 from 1 ratings, while DejaVocab averages 4.6 from 60 ratings.
Do Polyidiom or DejaVocab have ads?
Neither Polyidiom nor DejaVocab shows ads.
Which is updated more often, Polyidiom or DejaVocab?
Polyidiom ships an update every 3 days, and DejaVocab weekly. Most recently, Polyidiom was updated on October 8, 2026 and DejaVocab on October 25, 2026.

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