Moodle Mobile language strings customisation
Note: You are currently viewing documentation for Moodle 3.2. Up-to-date documentation for the latest stable version of Moodle is probably available here: 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 (You may have to install the Moodle Mobile Additional Features plugin if this option is not available in your menu. Details are found here: 
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:
For a complete list of string identifiers see this file:
There, in each line at the left (before the colons), is the string identifier. See the following example:
In the same line, at the right of the colons is the language string (in this case in English)