app-doc/gimp-help-0.10 ebuild is LINGUAS-aware, but will still waste time "compiling" (make) images/docs for other languages and will also install them, ignoring completely the LINGUAS variable.
You can set a LINGUAS value by means of an entry in /etc/portage/package.use, thus: $ grep linguas /etc/portage/package.use app-doc/gimp-help linguas_en You could argue that it takes a bit of detective work to find this, however. For the future it would be good if the ebuild were able to extract a value from the environment variable. In my case that would mean extracting "en" from "en_GB".
Thank you for report Denilson. This problem should be fixed in gimp-help-0.11-r1.