just wrote a tool a perl-script to include new variables in the master language-file (usually english) to all other languages plus a comment line, that it has to be translated. this saves the work if to manually check which new variables have been introduced f.e. in MG 3.4.0 and insert them into each language file. works also for scenrios and tutorials. it can be downloaded there:http://pastebin.de/13202
You need perl installed (haven't tried it on windows but should work with active-state-perl, just google it up). call it from the directory with the language-files with 2 parameters:
1. name of directory to create where the new files good (old ones stay untouched)
2. name of the master-language-file
now search for all line which need translation, do it and remove the comment-line afterwards.
i tested it on megaglest, but should work for any version of glest.