jpala16: Yes, QM file is very important. You can generate it from ts file in QT Linguist. Open QT Linguist -> open your TS file -> File -> Release As -> Qt message files for released applications Then replace name of file to for example qml_fi.qm (for testing purposes you replacing Finnish language), put it to /opt/usr/share/qmltube/qml/qmltube/i18n/ and in application you must to change language to Finnish. Now restart app and your lang is loaded. EDIT: BTW TS file is only language string source for QM files.