Localization Testing Template for Agile Teams

Start internationalization (i18n) architecture testing early in development. Verify that the product uses proper locale libraries, externalizes all strings, and supports character sets beyond ASCII. Localization (l10n) testing of translations starts when translations are ready, typically 2-4 weeks before launch in a new locale. Do not test translations incrementally as they trickle in. Test a complete translation set to catch context and consistency issues.

Test only when translation completeness is above 95% for a locale. Below that, the volume of "missing string" findings drowns out actual localization bugs. If you need to start earlier, focus on specific flows (e.g., onboarding, checkout) where translation is complete.

For linguistic review, yes. Machine translation quality has improved, but automated tools cannot evaluate whether a translation sounds natural, uses the right formality level, or avoids culturally inappropriate phrasing. For functional testing (dates, numbers, layout), any tester can verify formatting by comparing against the locale specification. But the linguistic review requires someone who reads and speaks the language fluently.

Pseudo-localization replaces English strings with modified text that simulates translation challenges: accented characters (replacing "a" with "ä"), string expansion (adding 30-50% more characters), and bracket wrapping ("[Translated Text]" to spot untranslated strings). Run pseudo-localization in development to catch i18n issues before real translations are available. Most i18n libraries (i18next, FormatJS) support pseudo-locale generation. The [e2e test template](/templates/e2e-test-template) can include a pseudo-locale configuration for automated layout checks.

Start with CSS logical properties (`margin-inline-start` instead of `margin-left`). Modern CSS frameworks support logical properties natively. Add `dir="rtl"` to the html element based on the active locale. Mirror directional icons (arrows, progress indicators) but keep non-directional icons unchanged. Test the full RTL layout as a dedicated effort. RTL is not "flip everything." Some elements (phone numbers, code snippets, media controls) remain left-to-right even in RTL contexts. ---