To ensure a multi-language GUI remains user-friendly:

1. Conduct user testing: Test with native speakers of each language to identify usability issues.

2. Follow localization best practices: Adapt GUI elements, formatting, and content to each language's conventions.

3. Use clear and simple language: Avoid jargon and complex terminology in translations.

4. Consistent layout and design: Maintain a consistent layout and design across languages.

5. Intuitive navigation: Ensure navigation elements are easily understandable across languages.

6. Cultural sensitivity: Consider cultural differences in icons, imagery, and content.

7. Right-to-left (RTL) support: Properly support RTL languages, such as Arabic and Hebrew.

8. Font and typography: Choose fonts that support all languages and are legible.

9. Color and imagery: Ensure colors and imagery are culturally appropriate and consistent.

10. Feedback mechanisms: Provide feedback mechanisms for users to report translation or usability issues.

11. Continuous testing and iteration: Regularly test and refine the GUI to ensure user-friendliness.

12. Consider language-specific features: Implement features specific to languages, such as Chinese input methods.

13. Use machine learning: Leverage machine learning to improve translation accuracy and user experience.

14. Provide language switching: Allow users to easily switch between languages.

15. Document translation guidelines: Establish guidelines for translators to ensure consistency.

By following these guidelines, you can ensure a user-friendly multi-language GUI that provides an inclusive experience for users worldwide.