translatable strings are present in several translation objects/ widget 'classes', like: mendix.widget.DialogMessage, mendix.lib.Validations, mxui.common, mxui.widget.DataGrid, etc. Some come from system texts, others from widgets, etc.
The syntax of mx.ui.translate is:
mx.ui.translate(<translate object name/ declared (widget) class name>, <key of translatable string>, <array of strings of placeholders, used in the translatable text>, <default text>)
However, it doesn't seem that enumerations are present anywhere in these objects. Normally, these are rendered server side in the page xml.