#Ei vs DejaLu
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
#Ei
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Official Experimentation Island App for 2026 Join, connect, and make the most of your Experimentation Island experience with the official app. From the moment you arrive on the island until the last session ends, the app is your ultimate companion to speak, tell, and connect.
DejaLu
This app helps you prepare to read specific French books by teaching you the vocabulary that appears in them first. It focuses on high-value words tied to the text you want to read, making reading feel less overwhelming and more achievable.
- Targeted vocabulary learning for specific books
- Vocabulary-first approach
- Short, focused review sessions
- Prepares learners for authentic French texts
- Motivating goal-oriented learning
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Read real books in French and German faster DejaLu helps you prepare for a specific book by teaching the vocabulary that appears in that book first. Instead of generic lessons, you train on high-value words tied to the text you actually want to read. Start with *Le Petit Prince* or *Emil und die Detektive*, complete short review sessions, and build the vocabulary you need to move through the story with more confidence. Why learners use DejaLu: - Targeted learning for one real book, not random word lists - Short, focused review sessions that fit into a busy schedule - Vocabulary-first approach that makes reading feel less overwhelming Who it is for: - French and German learners who want to start reading authentic books - Intermediate learners stuck between textbook French or German and real texts - Self-learners who want a concrete, motivating goal If your goal is to actually read in French or German, DejaLu gives you a practical path from study to story. Download DejaLu and start preparing for your first real book today.
Screenshots
Verdict
The clearest difference is in-app purchases: #Ei at none against DejaLu's 2. #Ei also leads on update cadence (daily vs every 3 weeks). On price, ads, device support and iOS requirement 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
Both are free to download. DejaLu sells 2 one-off in-app purchases. #Ei asks for nothing beyond the download.
#Ei ships an update daily, DejaLu every 3 weeks. The most recent releases landed on October 31, 2026 and November 5, 2026 respectively.
| Parameter | #Ei | DejaLu |
|---|---|---|
| Price | Free | Free |
| Rating | — | 5.0 (1 ratings) — better |
| Positive reviews | — | 100.0% of reviews |
| Number of ratings | — | 1 — better |
| Update frequency | Daily — better | Every 3 weeks |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | — | Free with in-app purchases |
| Devices | iPhone, iPod | iPhone, iPad, iPod — better |
| Requires iOS | 15.0 — better | 15.1 |
| Further details — not scored | ||
| Size | 41 MB | 30 MB |
| Age rating | 4+ | 4+ |
| Developer | Help je klant Holding B.V. | Implicit Knowledge, LLC |
In-app purchases
#Ei
No in-app purchases
DejaLu
- Le Petit Prince$9.99
- Emil und die Detektive$9.99









