I was translating pages from EN to ES, I realized today (after translation) that some of the pages were translated to the informal ES, while other pages were translated to the formal ES.
What can I do to synchronise all languages into either formal/informal?
Solution: You have the option to map your languages in WPML -> Languages -> Edit Languages and this is what is used for automatic translation. The translations themselves depend on which translation engine service you are using, and that is selected at WPML -> Translation Management -> Tools.