If you're uploading a custom language pack (usually a translation) all custom phrases (usually from hacks you've installed) will be removed by default.

To prevent this, you have to edit your language.xml-file applying the follwing changes:

First look for a line similar to <language name="English" vbversion="3.0.0" type="custom"> on the very top of the file and replace type="custom" with type="phrases".

After that find everything from <settings> to </settings> and remove it.

Save the file and now you should be able to upload the language to your Admin-CP without overwriting your custom phrases.


Notes:
For hackers: The create such a language first you have to enable debug-mode, which is recommended for hackers anyway ;). Then go to your Admin-CP -> Languages & Phrases -> Download / Upload Languages. There you choose the language to be downloaded and the filename for it and set Just fetch phrases (or however it is called in your translation) to Yes (Very important). If nothing went wrong you should have a language-pack, that won't remove any other phrases. (If you check the file it should look, as if you've applyed the changes stated above. :)

Important Note: Never (and I mean never ;)) touch the so called 'MASTER LANGUAGE' (The language-file in your install-folder) and never try to upload a master-language that has not been designed for your vBulletin-Version. And don't add any custom-phrases to it (The same goes for the other master-files) or you'll regret it sooner or later.