You're right, I've used technical terms because the intended
users are technical, but it would do no harm to use less
technical language in general.

Some of the abbreviations are there because to use the full word
or words makes the icons and text toolbar setting completely useless.
I'm not sure what to do about this one.

On abbreviations.

Such thinking is exactly the most problematic one: while it works for English,
there is almost no other language in which those strings translated will be as
short as in English, so you're still having the same problem, you just don't see
it right away (it'll show up in any localised instance of the program).

Also, I know that some applications use "priority labels" on toolbar buttons,
i.e. in "both-horiz", only some of the buttons have the text (try this with eg.
epiphany: "back" button has a label, and "forward" doesn't for me).

I actually had to stop for a second to realize what a "tabulator" was. Whether
or not abbreviations in general are a good idea, "tabulator" is absurd. It's
de-abbreviating, but it's also mangling the English.

The word 'diff' has different meanings in English than simple 'differences', as
well. The ordinary English word does not convey the sense of an exhaustive and
methodically-generated list of differences.

I'm also really curious on how "regular expression" is normally translated. You
can't of course translate it literally, since it's an idiom. But it's not the
sort of idiom that every language would have an equivalent to, because it's so
new and so specialized. Is it normally translated at all? Just curious.

Mabye what your target language neeeds is more abbreviations :)

I generally translate "regular expression" as a translation of adjective
"regular" and noun "expression".

You're arguing for abbreviations which can't be less technical, for which I
clearly stated the reasons: make translators feel comfortable with using longer
strings.  

If using technobabble is a must, then there are other solutions to the above
problem: explicitely mention in a comment for translators what above words mean
("tab is a tabulator character, and you can translate it as such", "regex stands
for regular expression, which is probably more suitable for translation")

Answer to question if those are translated at all can be found easily on the web
(try viewing translations of http://www.php.net/pcre -- for instance, German
translation also replaces "regex" with full expression, or check Chinese,
Russian which are even more evident since they're not using Latin script)

One exception is "diff", where you're arguing the usefulness of recognizing it
as a mechanism present in standard POSIX systems (it's NOT English, at least no
online English dictionary gives it more than "slang for difference") vs.
usefulness to those unfamiliar with POSIX and diff command line utility (i.e. IT
people, and not all of them either) who would recognise meaning of "differences"
as something for showing differences between files.  FWIW, your point also seems
moot since Meld already has other strings which explicitely state "File
Differences Viewer" (or something like that).  It's just a choice of making it
harder for translators and new users vs. making it harder for those who can use
"diff" from command line anyway.

Also, I appreciate your willingness to help others' native languages by
introducing more abbreviations, but it's not up to one foreign person to dictate
how tens of other languages are going to evolve ;-) 

I've looked through the .pot file, fixing the original points raised,
plus some more and trying to remove similar strings. Looking at the
.pot file was quite illuminating.

Batch close of old bugs.