# Languages Supported by the --language Parameter in Understand Anything

> Discover languages supported by the --language parameter in Understand Anything. Use ISO 639-1 codes, aliases, or locale variants for customized output.

- Repository: [Egonex/Understand-Anything](https://github.com/Egonex-AI/Understand-Anything)
- Tags: api-reference
- Published: 2026-06-23

---

**The `--language` parameter accepts ISO 639-1 codes (e.g., `en`, `zh`, `ja`), friendly aliases (e.g., `english`, `chinese`), and locale-specific variants (e.g., `zh-TW`, `en-US`) to localize all textual output, defaulting to English (`en`) when omitted.**

The `--language` flag controls the language used for generating summaries, descriptions, tags, titles, and educational content in the **Understand Anything** CLI tool from the Egonex-AI/Understand-Anything repository. This parameter processes multiple input formats and persists your selection across sessions in the project configuration. Whether generating Japanese code explanations or Spanish dashboard labels, the tool adapts its entire textual output to your specified locale.

## Supported Language Formats

### ISO 639-1 Standard Codes

The primary input format follows the two-letter ISO 639-1 standard. According to [`understand-anything-plugin/skills/understand/SKILL.md`](https://github.com/Egonex-AI/Understand-Anything/blob/main/understand-anything-plugin/skills/understand/SKILL.md), the tool recognizes standard codes including `en` (English), `zh` (Chinese), `ja` (Japanese), `ko` (Korean), `es` (Spanish), `fr` (French), and `de` (German).

### Friendly Aliases

For usability, the parser also accepts full language names as valid inputs. You can use `english`, `chinese`, `japanese`, `korean`, `spanish`, `french`, or `german` as alternatives to their abbreviated ISO codes.

### Locale-Specific Variants

Regional dialects and localization variants are supported using hyphenated locale identifiers. Valid examples include `zh-TW` (Traditional Chinese, Taiwan), `zh-HK` (Traditional Chinese, Hong Kong), `en-GB` (British English), and `en-US` (American English).

## How to Use the --language Flag

Pass the desired language code or alias immediately after the flag when invoking the CLI:

```bash

# Generate output in Simplified Chinese

understand --language zh

# Generate output in Traditional Chinese (Taiwan)

understand --language zh-TW

# Generate output in Japanese

understand --language ja

# Generate output in Korean

understand --language ko

# Generate output in Spanish

understand --language es

# Generate output in French

understand --language fr

# Generate output in German

understand --language de

```

These commands produce localized dashboards, summaries, code explanations, and metadata in the requested language, as documented in the repository's [`README.md`](https://github.com/Egonex-AI/Understand-Anything/blob/main/README.md) and language-specific guides like [`READMEs/README.zh-CN.md`](https://github.com/Egonex-AI/Understand-Anything/blob/main/READMEs/README.zh-CN.md) and [`READMEs/README.ja-JP.md`](https://github.com/Egonex-AI/Understand-Anything/blob/main/READMEs/README.ja-JP.md).

## Configuration Persistence

When you specify a language, the tool automatically saves your preference to [`.understand-anything/config.json`](https://github.com/Egonex-AI/Understand-Anything/blob/main/.understand-anything/config.json) in your project root. This persistence mechanism ensures subsequent runs reuse the same language setting without requiring repeated flag usage. If the flag is omitted and no configuration exists, the system defaults to `en` (English) as defined in the skill specification.

## Summary

- The `--language` parameter accepts **ISO 639-1 codes**, **friendly aliases**, and **locale-specific variants**
- Supported codes include `en`, `zh`, `ja`, `ko`, `es`, `fr`, `de`, with regional variants like `zh-TW` and `en-GB`
- Defaults to English (`en`) when not specified and no prior configuration exists
- Settings persist automatically in [`.understand-anything/config.json`](https://github.com/Egonex-AI/Understand-Anything/blob/main/.understand-anything/config.json) across sessions
- Behavior is defined in [`understand-anything-plugin/skills/understand/SKILL.md`](https://github.com/Egonex-AI/Understand-Anything/blob/main/understand-anything-plugin/skills/understand/SKILL.md)

## Frequently Asked Questions

### What happens if I don't specify the --language parameter?

If you omit the flag, the tool checks [`.understand-anything/config.json`](https://github.com/Egonex-AI/Understand-Anything/blob/main/.understand-anything/config.json) for a previously saved language preference. If no configuration file exists, it defaults to English (`en`) for all generated output including summaries, descriptions, and code explanations.

### Can I use full language names instead of codes?

Yes. The parser accepts friendly aliases such as `english`, `chinese`, `japanese`, `korean`, `spanish`, `french`, and `german` alongside standard ISO 639-1 two-letter codes, making the CLI more accessible for users unfamiliar with ISO standards.

### Does the tool support regional dialects like Traditional Chinese?

Yes. Locale-specific variants are fully supported, including `zh-TW` (Traditional Chinese, Taiwan), `zh-HK` (Traditional Chinese, Hong Kong), `en-GB` (British English), and `en-US` (American English), allowing for region-specific localization of generated content.

### Where is the language configuration stored?

Your selected language is persisted in [`.understand-anything/config.json`](https://github.com/Egonex-AI/Understand-Anything/blob/main/.understand-anything/config.json) within your project directory. This ensures that subsequent runs of the tool maintain your localization preferences without requiring you to pass the `--language` flag repeatedly.