TYPO3 v7 has reached its end-of-life November 30th, 2018 and is not maintained by the community anymore. Looking for a stable version? Use the version switch on the top left.
There is no further ELTS support. It is recommended that you upgrade your project and use a supported version of TYPO3.
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.