Moodle Mobile language strings customisation
Words and phrases displayed in the app can be customised via the "Custom language strings" (customlangstrings) setting in Administration > Site administration > Mobile app > Mobile features
Enter each custom language string on a new line with format: string identifier, custom language string and language code, separated by pipe characters. For example:
mm.user.student|Learner|en mm.user.student|Aprendiz|es
For a complete list of string identifiers see this file:
On each line at the left (before the colons), is the string identifier.
In the same line, at the right of the colons is the language string (in this case in English)