Joomla - Language Files

When naming Joomla language files, it is important to remember that the extension group name is used. The language filename uses the extension group name after the extension prefix. For example,

somebutton.xml
<extension version="3.4" type="plugin" group="editors-xtd">
    ...
    <languages folder="language">
        <language tag="en-GB">en-GB/en-GB.plg_editors-xtd_somebutton.ini</language>
        <language tag="en-GB">en-GB/en-GB.plg_editors-xtd_somebutton.sys.ini</language>
    </languages>
</extension>