Within a namespace, you can refer to things by their name. To refer to things in another namespace, you have to qualify the name. This qualification can be explicit or implicit, however.
In real life, we usually don’t think about namespaces, because most names clearly indicate what kind of things we are talking about. “yellow” is a color, “birch” is a tree. We don’t have to qualify “yellow” as the name of a color, because we know it implicitly.
When programming, however, namespaces are more important: When talking of attributes, many different things can have the “id-number 45268”. If all things exist in the same namespace, we assume that 45268 uniquely identifies something. If people, projects, and companies all exist in their own namespace, we have to qualifiy the id-number. Is it the id-number of a person, a project, a company?
This means any PageTitle? (any DataBase entry from any wikis in the precedence list), even those with spaces is immediately linked without any freedom of the author to stop it except for them adjust their PrivateNamespace?.
PrivateNamespaces? should probably start with nothing defined with obvious settings (cookie saved checkboxes) to allow quick and broad adjustments that include entire wikis at a time, so, for instance, whenever you write the word wiki in a sentence (no matter the case, and not surrounded by ’), it would try to resolve that word or phrase from a list of wikis ordered by precedence of credibility (according to you), and finally having some easily switched-on default such as wikipedia as a catchall if you like lots of links in your comments.
You should also be able to define just one word or phrase at a time.
In a wiki page’s DefinitionArea?, the local NaturalLinkLanguage?, would be used when rendering the page. An author writing in the DefinitionArea? of the page would have no control over what does and doesn’t link, and where those links point except to vote for your preference (or try to adjust those pages directly).
In other words, if you like the word ‘wiki’ to resolve to MeatBall instead of WikiPedia, you would change the link resolution “lookup order” in your PrivateNamespace? (you could reorder just that word, or you might want to reorder the wikis (so MeatBall always takes precedence over WikiPedia)).
Your PrivateNameSpace? should probably not readable by the wiki software by default for privacy reasons? It could be kept encrypted on the server if that is needed.
The problem that human language is context sensitive (eg. a tree can be a plant or a math concept, depending on the kind of book you are reading), where as link language on a particular wiki is not (the Tree link will always point to the same page) can be solved in different ways: