No subject

version of Etoys both GetTextTranslator and InternalTranslator
(refactored from legacy NLS) inherit common abstract class
NaturalLanguageTranslator and share some interfaces.
You could review these in Etoys source code.

So the code:
 'Syntax error on line {1}' translated format: { linenumber }.
will work with both gettext based translation and legacy NLS.

What has not been built yet is the facility to translate user objects
in project (*.pr) ,
translate text of Morph instances for example.

I might not be able to understand what you are worrying very well.
So please ask again with more detail if you want...

Cheers,
/Korakurider