text: Uhm, there are. Many forms of Creole are found in the Carribean and Louisiana, all evolved from French into something more or less distinct. While similar enough to French that a French-speaker could usually understand the gist of what is being said in Creole and that a Creole speaker could make himself better understood with effort, it's separate enough that someone actually has to study the other to speak it fluently. Louisiana Creole takes this evolution from French further and incorporates some expressions from English.\n\n\nAnother half-languages you might be interested in is Luxumburgian, which evolved from a Dutch dialect with influences from French. Something possibly on the way to becoming a half-language is the difference between Quebecois French, which is similar to medieval French, and the more modern French spoken in France, and the deriviations found in western Africa. Another possibility is the differences between the various Englishes of the US alone. Can a Californian understand the heavy drawl of a Southerner or New Englander? Not easily, if at all, and I'm not even mentioning all the dialects of the British Isles.\n\nWhenever you see languages in the same family, they came from half-languages and sometimes still are effectively half-languages. Latin evolved separately in France, Spain, Italy, and Romania, though for a short enough time each was still only a regional dialect or half-language and could be understood by each other, especially if they made the effort to enunciate clearly. We can see the slow shifting of German as it went from the west to east through Europe, eventually becoming English. A German can sometimes understand the gist of Dutch even today with a lot of work, and vice versa.