Can I restrict who is allowed to edit my translations?

Yes you can, and you probably should.

A project (or a distribution) can assign a "translation group" to manage its translations. The translation group assigns a "translation team" for every language it supports. An existing translation group may agree to take your project under its wing, or you can file a request (under Answers, for the rosetta application) to have one created.

Once you have set a translation group for your project, you can choose from four different access models:

 - Open. This is the default, and an easy way to get started with translating a project. Any Launchpad user can edit the translations.

 - Structured. In languages that the translation group assigns a translation team for, any Launchpad user can enter suggestions but only members of the translation team can update the actual translation. In other languages, anyone can edit as with Open. This is a good way to start organizing your translation, but still attract initial translators for languages you can't cover yet.

 - Restricted. As with Structured, in languages that are covered by the translation group, anyone can enter suggestions and only translation team members can approve or edit them. But for other languages, the translations are read-only. This is a good choice once your project has matured and quality of your translations becomes a bigger concern than coverage. It's also the best choice if your project only wants to use Launchpad for a limited number of languages. (You don't want to invite people to contribute to translations that you're not going to use).

 - Closed. People outside the translation group can see the translations, but can't enter anything. Use this if you want only a limited group of people—the translation group members—to work on the translation.