ISO 639-1
to Tonga (Tonga Islands)
· filed 2026-07-18 · click a code to copy
Tonga (Tonga Islands) carries the ISO 639-1 two-letter code to.
In practice this code appears in HTML (<html lang="to">), HTTP Accept-Language headers, locale identifiers such as to-XX, subtitle tracks and translation files — anywhere software needs to say “this content is in Tonga (Tonga Islands)”.