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.
Usually local translation is the first option, and the last options are in English.
> Note to translators:
> Please include the English words as synonyms.
> This allows people from other wikis to contribute more easily.