# 化學之書 vs DSE AI Speak

The clearest difference is in-app purchases: 化學之書 at none against DSE AI Speak's 3. 化學之書 also leads on update cadence (every 3 weeks vs every 2 months) and iOS requirement (17.0 vs 26.2). On price, ads and device support there is nothing between them.

Both are free to download. DSE AI Speak sells 3 in-app purchases, starting at $3.99 per month. 化學之書 asks for nothing beyond the download.

化學之書 ships an update every 3 weeks, DSE AI Speak every 2 months. The most recent releases landed on October 27, 2026 and October 25, 2026 respectively.

## The numbers

| Metric | 化學之書 | DSE AI Speak |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | **Every 3 weeks** | Every 2 months |
| Size | 55 MB | 1 MB |
| Requires iOS | **17.0** | 26.2 |
| Devices | **iPhone, iPad** | iPhone |
| Age rating | 12+ | 4+ |
| Developer | [BUDDHIST HO NAM KAM COLLEGE](https://appshunter.io/developer/1532349038) | [Kin Fai Lee](https://appshunter.io/developer/531306021) |

## What reviewers say

### 化學之書

[App page](https://appshunter.io/ios/app/id1512573867)

**Features:** Vision Pro support

**In-app purchases:** none


### DSE AI Speak

[App page](https://appshunter.io/ios/app/dse-ai-speak/id6761884607)

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

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Basic Plan | $3.99 | per month |
| Advanced Plan | $9.99 | per month |
| Elite Plan | $12.99 | per month |


## Frequently asked questions

### Is 化學之書 free?

化學之書 is free to download, with no in-app purchases.

### Is DSE AI Speak free?

DSE AI Speak is free to download, with in-app purchases available.

### Do 化學之書 or DSE AI Speak have ads?

Neither 化學之書 nor DSE AI Speak shows ads.

### Which is updated more often, 化學之書 or DSE AI Speak?

化學之書 ships an update every 3 weeks, and DSE AI Speak every 2 months. Most recently, 化學之書 was updated on October 27, 2026 and DSE AI Speak on October 25, 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.*