i18n

Format monetary values, numbers, and dates using the browser's built-in Intl.NumberFormat and Intl.DateTimeFormat APIs instead of manual string manipulation.

Select the correct grammatical plural category for every language using Intl.PluralRules or an ICU-aware i18n library instead of simple singular/plural branching.

Hreflang tags indicate language and regional variations for multilingual sites.

Ensure that layouts use flexible sizing so that translated text — which can be 30–50% longer than English — does not overflow, clip, or break the UI.

Default to abstract, culture-neutral icons and illustrations, and supply locale-specific image variants only when visual content carries meaning that differs across regions.