localization

Translation is only the first layer

Internationalization (i18n) is the engineering groundwork that makes a store adaptable: Unicode support, no hard-coded strings, room for text expansion. Localization is the market-facing work on top. W3C defines it as adapting a product to “the language, cultural and other requirements of a specific target market,” which means currency and price formatting, date and address conventions, units, payment methods, imagery, and copy that reads like a local wrote it.

For search, localization has to be declared, not guessed. Google treats regional variants of the same page as duplicates only when the main content stays untranslated, so a UK page that differs mainly by GBP pricing still needs an explicit signal. That signal is hreflang, and every version must reference itself plus all siblings:

<link rel="alternate" hreflang="en-gb" href="https://example.com/uk/product" />
<link rel="alternate" hreflang="en-us" href="https://example.com/us/product" />
<link rel="alternate" hreflang="x-default" href="https://example.com/product" />

Use x-default for shoppers whose settings match none of your locales, and avoid IP-based redirects. Google says IP location analysis is difficult and generally not reliable, and it can stop crawlers from seeing your other locales. When two regional URLs share one language, give each a self-referencing rel="canonical" in that language, never point one at the other, or Google can collapse the cluster and drop a version.