In which cases are localization and internationalization considered functional tests, and in which cases are they non-functional?

Localization (L10n) and Internationalization (I18n) as functional tests:

• Verification of the correctness of translation of texts, messages, interface elements according to local standards and language features.
• Testing data formatting (dates, times, numbers) according to local rules.
• Checking the correctness of currency and measurement units application.
• Testing functionality dependent on regional settings (e.g., address search, map services).

Localization (L10n) and Internationalization (I18n) as non-functional tests:

• Verification of page load performance and interface element responsiveness across different localizations.
• Testing system scalability when working with a large number of locales and languages.
• Usability testing of the interface for users from different cultural groups.
• Compatibility testing with various operating systems, browsers, and devices when using different locales.
• Data security verification and compliance with regional privacy regulations.