Localization glossary
TermMeaning
i18nInternationalization. Designing and building software so it can be adapted to any locale — without changing the code again later. The 18 is the number of letters between the i and the n.
l10nLocalization. Actually adapting an internationalized product to one specific locale: translating text, adjusting formats, sometimes changing imagery or layout.
LocaleLocale identifier. A language plus a region and optional script, written as a BCP 47 tag: pt-BR, sr-Latn-RS, zh-Hant-TW. Language alone is rarely enough.
CLDRCommon Locale Data Repository. Unicode's database of locale facts: plural rules, date patterns, number formats, collation, currency display. Almost every correct i18n library reads from it.
ICU MessageFormatMessage syntax. A message format supporting plurals, gender selection and nested arguments in a single string, so translators can restructure a sentence rather than receive it in fragments.
POT / PO / MOGettext catalogues. POT is the extracted template, PO is a translated catalogue for one locale, MO is the compiled binary the program loads at runtime.
FuzzyFuzzy match. A gettext flag meaning “this translation was carried over from a similar string and has not been confirmed”. Fuzzy strings are not used at runtime until a human confirms them.
TMTranslation memory. A database of previously approved source/target pairs, used to suggest translations for new or changed strings. Exchanged as TMX.
TB / GlossaryTermbase. The list of terms that must always be translated the same way, with definitions and forbidden alternatives. Exchanged as TBX.
MQMMultidimensional Quality Metrics. An open framework for classifying translation errors by type and severity, producing a comparable quality score instead of an opinion.
MTPEMachine translation post-editing. A human editing machine output to a defined quality level — “light” for gist, “full” for publication-grade.
BidiBidirectional text. Text mixing right-to-left and left-to-right runs. The Unicode Bidirectional Algorithm decides display order; isolation characters keep embedded runs from corrupting it.
PseudolocalizationPseudo-locale. A fake locale that lengthens and accents strings ([!!! Ŝàvé çĥàñĝéŝ !!!]) to expose truncation, clipping and hard-coded text before real translation starts.
String freezeFreeze. A point in the release cycle after which source strings cannot change, giving translators a stable target. Breaking a freeze is the fastest way to lose volunteers.