# Keyword Understanding vs TriStack

The clearest difference is price: TriStack at $6.99 against Keyword Understanding's $17.99. TriStack also leads on update cadence (every 2 months vs every 10 months). On ads, in-app purchases, device support and iOS requirement there is nothing between them.

Keyword Understanding costs $17.99 and TriStack $6.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Keyword Understanding ships an update every 10 months, TriStack every 2 months. The most recent releases landed on October 8, 2026 and October 3, 2026 respectively.

## The numbers

| Metric | Keyword Understanding | TriStack |
| --- | --- | --- |
| Price | $17.99 | **$6.99** |
| Rating | **[5.0 (3 ratings)](https://appshunter.io/ios/app/keyword-understanding/id816979055/reviews)** | — |
| Number of ratings | **3** | — |
| Positive reviews | 25.0% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 10 months | **Every 2 months** |
| Monetization | Paid | — |
| Size | 64 MB | 36 MB |
| Requires iOS | **15.0** | 15.1 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Aptus Speech and Language Therapy Limited](https://appshunter.io/developer/1482673468) | [SimTeCon GmbH](https://appshunter.io/developer/1761797043) |

## What reviewers say

### Keyword Understanding

[App page](https://appshunter.io/ios/app/keyword-understanding/id816979055)

This app helps users of all ages improve their ability to understand spoken and written directions. It features various activities targeting vocabulary, basic concepts, and sequential instructions, making it beneficial for individuals with listening comprehension or processing difficulties.

**Highlights:** Follow spoken and written directions, Improve vocabulary and basic concepts, Target auditory attention and working memory, Activities for one and two-step directions, Temporal and sequential direction practice, Comprehension check for vocabulary and concepts

**Features:** macOS Compatibility

**In-app purchases:** none


### TriStack

[App page](https://appshunter.io/ios/app/tristack/id6743567658)

**In-app purchases:** none


## Frequently asked questions

### Is Keyword Understanding free?

Keyword Understanding costs $17.99, with no in-app purchases.

### Is TriStack free?

TriStack costs $6.99, with no in-app purchases.

### Do Keyword Understanding or TriStack have ads?

Neither Keyword Understanding nor TriStack shows ads.

### Which is updated more often, Keyword Understanding or TriStack?

Keyword Understanding ships an update every 10 months, and TriStack every 2 months. Most recently, Keyword Understanding was updated on October 8, 2026 and TriStack on October 3, 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.*