# Vowels Central Diphthong vs Estill Exercises

The clearest difference is price: Estill Exercises at Free against Vowels Central Diphthong's $4.99. Estill Exercises also leads on update cadence (every 6 weeks vs every 37 months). Vowels Central Diphthong's advantage is in-app purchases (none vs 1) and iOS requirement (11.0 vs 14.0). On ads and device support there is nothing between them.

Estill Exercises is free to download; Vowels Central Diphthong costs $4.99 up front. Estill Exercises sells 1 in-app purchase, starting at $9.99 per month. Vowels Central Diphthong asks for nothing beyond the download.

Vowels Central Diphthong ships an update every 37 months, Estill Exercises every 6 weeks. The most recent releases landed on October 23, 2026 and October 17, 2026 respectively.

## The numbers

| Metric | Vowels Central Diphthong | Estill Exercises |
| --- | --- | --- |
| Price | $4.99 | **Free** |
| Rating | — | **[5.0 (2 ratings)](https://appshunter.io/ios/app/estill-exercises/id1526848882/reviews)** |
| Number of ratings | — | **2** |
| Positive reviews | — | 37.5% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 37 months | **Every 6 weeks** |
| Monetization | — | Subscription |
| Size | 31 MB | 16 MB |
| Requires iOS | **11.0** | 14.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Blue Tree Publishing, Inc.](https://appshunter.io/developer/496143325) | [Estill Voice International, LLC](https://appshunter.io/developer/1222358364) |

## What reviewers say

### Vowels Central Diphthong

[App page](https://appshunter.io/ios/app/vowels-central-diphthong/id731753490)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


### Estill Exercises

[App page](https://appshunter.io/ios/app/estill-exercises/id1526848882)

Master vocal techniques with guided exercises and expert instruction. Track your progress, review study materials in multiple languages, and connect with a community of learners. Perfect for both beginners and experienced users looking to refine their voice.

**Highlights:** Personalized user center with notes and bookmarks, Study materials in 6 languages, Expert-guided video lessons, Progress tracking and practice logging, Audio training exercises, Interactive flashcards for exam prep, Attractor state check-in

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Estill Exercises Monthly | $9.99 | per month |


## Frequently asked questions

### Is Vowels Central Diphthong free?

Vowels Central Diphthong costs $4.99, with no in-app purchases.

### Is Estill Exercises free?

Estill Exercises is free to download, with in-app purchases available.

### Do Vowels Central Diphthong or Estill Exercises have ads?

Neither Vowels Central Diphthong nor Estill Exercises shows ads.

### Which is updated more often, Vowels Central Diphthong or Estill Exercises?

Vowels Central Diphthong ships an update every 37 months, and Estill Exercises every 6 weeks. Most recently, Vowels Central Diphthong was updated on October 23, 2026 and Estill Exercises on October 17, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*