http://www.gnu.org/software/gettext/manual/html_node/gettext_219.html#SEC219

This all began in July 1994, when Patrick D'Cruze had the idea and
initiative of internationalizing version 3.9.2 of GNU fileutils. He
then asked Jim Meyering, the maintainer, how to get those changes
folded into an official release. That first draft was full of #ifdefs
and somewhat disconcerting, and Jim wanted to find nicer ways. Patrick
and Jim shared some tries and experimentations in this area. Then,
feeling that this might eventually have a deeper impact on GNU, Jim
wanted to know what standards were, and contacted Richard Stallman, who
very quickly and verbally described an overall design for what was
meant to become glocale, at that time.

[...]

While Jim took some distance and time and became dad for a second time,
Roland wanted to get GNU libc internationalized, and got Ulrich Drepper
involved in that project. Instead of starting from glocale, Ulrich
rewrote something from scratch, but more conformant to the set of
guidelines who emerged out of the glocale effort. Then, Ulrich got
people from the previous forum to involve themselves into this new
project, and the switch from glocale to what was first named msgutils,
renamed nlsutils, and later gettext, became officially accepted by
Richard in May 1995 or so.

Let's summarize by saying that Ulrich Drepper wrote GNU gettext in
April 1995. The first official release of the package, including PO
mode, occurred in July 1995, and was numbered 0.7. Other people
contributed to the effort by providing a discussion forum around
Ulrich, writing little pieces of code, or testing. These are quoted in
the THANKS file which comes with the GNU gettext distribution.

There's no mention of prior art.