MessagesXx.php magic words should be re-factored so the first alias of each magic word is the "most preferred" one. According to T53852#1735780, VisualEditor would then use MagicWord::getSynonym( 0 ) to find out what's the preferred localised form, instead of hardcoding the least preferred version as it currently does.
Usually local translation is the first option, and the last options are in English.
(MessageEn.php)Note to translators: Please include the English words as synonyms. This allows people from other wikis to contribute more easily.