This is the Wikimedia Incubator, where potential Wikimedia project wikis in new-language versions of Wikipedia, Wikibooks, Wikinews, Wikiquote, Wiktionary and Wikivoyage can be arranged, written, tested and proven worthy of being hosted by the Wikimedia Foundation.
Although test wikis in the Wikimedia Incubator do not get their own wiki domains, they can be read and edited just like any other Wikimedia project wiki.
New language versions of Wikiversity should go to Beta Wikiversity, and those of Wikisource to Multilingual Wikisource.
You cannot start an entirely new project here, you may only start a new-language version of an existing project. If you want to start a new project, go to meta:proposals for new projects.