Echoes vs Sylvi
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Echoes
Visualize and record your heartbeat using your smartphone. Contribute to anonymized research at King's College London and Maastricht University to advance heart diagnosis technologies.
- Hear and visualize heartbeat
- Save heart sound recordings
- Observe heart sound evolution
- Contribute to anonymized research
- Understand heart diagnosis limits
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Echoes allows you to hear and visualise the beauty of your heartbeat, simply using your smartphone. Save your recording and observe your heart sounds evolving. Every app user will contribute to an anonymous online archive at King’s College London and Maastricht University, helping researchers to understand the limits of heart diagnosis through mobile technologies.
Sylvi
Practice foreign languages with AI penpals who provide tutor-level feedback on every message. Learn essential phrases, build vocabulary, and stay motivated with friends. Offers a free trial before subscription.
- AI penpals for language practice
- Real-time message correction and explanation
- Vocabulary building and memorization tools
- Practice with friends
- Streak preservation
- Flashcards and leaderboard
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AI penpals that feel like native friends. Tutor-level feedback on every single message. That's Sylvi. You can even pick a penpal with the exact accent you want to have. French (France and Canada) Spanish (Spain, Mexico, Colombia, Puerto Rico, etc) German Italian Portuguese (Portugal and Brazil) English (UK, US, Australia) More languages coming soon - follow our journey on @sylvi_app Too shy to talk to a native speaker? Practice with AI penpals who know you well enough to ask about your day. Every message you send is corrected and explained in real time - not just flagged, but actually taught, so when the real moment comes, you're ready for it. - Learn the phrases you need, for the life you lead Build your vocabulary by saving words important to you. Test yourself daily to memorise them. - Stay accountable with friends Practice with your friends regardless of what language they're learning or what level they're at. "I've used a lot of different language apps... but Sylvi has been the one I've been having the most success with growth-wise. At least from what my tutor tells me." Can't bear to lose your streak? We won't tell. If you've got a streak you can't bear to lose, message us at support@sylvi.ai and we'll transfer it straight to Sylvi. Try us free for 1 week, then pick a subscription that works for you. "I know grammar. I know all of these vocabularies, but you're kind of stuck in the middle of like - how do I become comprehensible? Then I found Sylvi" - Amira, UK "I could say, 'I'm going to the cinema today'. Then if I do Sylvi tomorrow, my penpal will come back and say, 'so what film did you see at the cinema?'. I love the continuity. It's so clever." - James, US
Screenshots
Verdict
The clearest difference is review sentiment: Sylvi at 83% against Echoes's 38%. Sylvi also leads on rating (4.7 vs 3.3) and ratings volume (338 vs 24). Echoes's advantage is in-app purchases (none vs 25) and iOS requirement (10.0 vs 16.4). On price, ads and device support 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. Sylvi sells 24 in-app purchases, starting at $2.99 per month. Echoes asks for nothing beyond the download.
Sylvi holds the better App Store score, 4.7 against 3.3. That said, the two scores are not equally well evidenced: Sylvi has 338 ratings behind it against 24, so its average is the more settled of the two. Written reviews point the same way: 38% of Echoes's written reviews are positive against 83% of Sylvi's.
| Parameter | Echoes | Sylvi |
|---|---|---|
| Price | Free | Free |
| Rating | 3.3 (24 ratings) | 4.7 (338 ratings) — better |
| Positive reviews | 37.5% of reviews | 83.2% of reviews — better |
| Number of ratings | 24 | 338 — better |
| Update frequency | — | Every 3 days |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | Free — better | Free with in-app purchases |
| Devices | iPhone, iPod | iPhone, iPad |
| Requires iOS | 10.0 — better | 16.4 |
| Further details — not scored | ||
| Size | 79 MB | 143 MB |
| Age rating | 4+ | 12+ |
| Developer | King's Mobile | Sylvi Ltd |
Customer experience
Echoes
Sylvi
Bugs and requests
Echoes
Not enough reviews yet to summarise bugs or requests.
Sylvi
Reported bugs
3 issues- Frequent app crashes
- Subscription issues
- Inconsistent user experience
Requested features
5 requests- Expand language options
- Improve free version features
- Implement more personalized learning
- Add more advanced conversation scenarios
- Improve speech recognition accuracy
In-app purchases
Echoes
No in-app purchases
Sylvi
- Sylvi Lite (Monthly)7 Days trial$2.991 Month
- Sylvi Lite (Monthly)$2.991 Month
- Sylvi Pro (Monthly)$6.991 Month
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- Sylvi Pro (Monthly)7 Days trial$6.991 Month
- Sylvi Lite (Monthly)$6.991 Month
- Monthly14 Days trial$9.991 Month
- Monthly7 Days trial$13.991 Month
- Sylvi Pro (Monthly)$14.991 Month
- Monthly7 Days trial$19.991 Month
- 3 months14 Days trial$19.993 Months
- Sylvi Lite (Annual)14 Days trial$23.991 Year
- Sylvi Lite (Annual)$23.991 Year
- Monthly7 Days trial$24.991 Month
- Sylvi Lite (Annual)$35.991 Year
- 3 months14 Days trial$39.993 Months
- 3 months7 Days trial$39.993 Months
- Annual14 Days trial$49.901 Year
- Annual7 Days trial$59.991 Year
- Sylvi Pro (Annual)14 Days trial$59.991 Year
- Sylvi Pro (Annual)$59.991 Year
- Sylvi Pro (Annual)$79.991 Year
- Annual14 Days trial$83.901 Year
- Annual7 Days trial$89.991 Year
- Annual7 Days trial$129.991 Year
