I'm trying via ext_localconf.php of my own extension to override the locallang files for the news extension. So I placed in my own extension following lines:
$GLOBALS['TYPO3_CONF_VARS']['SYS']['locallangXMLOverride']['EXT:news/Resources/Private/Language/locallang.xlf'][] = 'fileadmin/template/html/news/Private/Language/locallang.xlf';
$GLOBALS['TYPO3_CONF_VARS']['SYS']['locallangXMLOverride']['sw']['EXT:news/Resources/Private/Language/locallang.xlf'][] = 'fileadmin/template/html/news/Private/Language/sw.locallang.xlf';
That just works for the default file.
When I'm writing
$GLOBALS['TYPO3_CONF_VARS']['SYS']['locallangXMLOverride']['EXT:news/Resources/Private/Language/locallang.xlf'][] = 'fileadmin/template/html/news/Private/Language/locallang.xlf';
$GLOBALS['TYPO3_CONF_VARS']['SYS']['locallangXMLOverride']['EXT:news/Resources/Private/Language/locallang.xlf']['sw'] = 'fileadmin/template/html/news/Private/Language/sw.locallang.xlf';
then its using the second file for everything. Trying to override EXT:news/Resources/Private/Language/sw.locallang.xlf doesn't work either.
When I switch the both lines above its using the default file in every language. I also created a file sw.locallang.xlf in news extension so that this exists. But ofcourse I dont want to need this file there because of the update issue.
I tried a lot of other codes too I could found, but nothing worked for me.
Somebody knows the correct way to use this translation files? Its TYPO3 7.6