ohh, no wonder it doesn't work in the way you want.
I didn't understand you use another news plugin, and want to show captions on the news page, not on the page you show news with anynews.
After looking inside plugin's code, I see that it's more a duplicate of news plugin.
It should process automatically translations files from language directory.
But I don't see it makes own directory during installation process.
If it has own directory in /modules, copy languages directory from /modules/news to archive plugin's directory.
If it deleted /modules/news during install, and overwrote it, copy news languages directory from WB archive.
I don't have any more ideas, as I'd have to test it more, and atm I have very little time because of deployment.
edit: no wonder I didn't get what you were talking about.
Earlier solution should be working perfectly with anynews-archive module (containing 3 files).
Do a simple test by pasting
<?php echo LANGUAGE ?>
somewhere in your template, to see the current page's language. String which will be shown is the case string of the condition to show readmore text.
If this "snippet" shows
DE on in e.g. spanish news page, then solution I posted won't work for logical purposes.
you can use also if/elseif in the way
if (LANGUAGE == "EN") {
$readmore_text="Read more";
} elseif (LANGUAGE == "DE") {
$readmore_text = "Weiter lesen";
} elseif (LANGUAGE == "WHATEVER") {
$readmore_text = "WHATEVER more";
}
and so on