Outdated TYPO3 Version
This documentation refers to an outdated TYPO3 version - either select a supported version or make sure to use a TYPO3 Extended Long Term Support (ELTS) version to continue getting security updates.
Internationalization is achieved in TYPO3 with the use of files containing localizable strings. Since TYPO3 CMS 4.6, the XLIFF format is used. It is described further in this section. Until TYPO3 CMS 4.5, a proprietary format called “locallang XML” was used.