The Northeast Asia is one of the unique points on the globe where there are many language isolates and portmanteau families. From a conservative point of view, the Japanese language is a member of such a portmanteau family that has recently and increasingly been called Japonic in the Western literature. While Japanese is unquestionably a member of this Japonic language family, which consists of two Japanese languages (Japanese itself and the moribund Hachijō language) and four or five relatively closely related Ryūkyūan languages (Amami, Okinawan, Miyako, Yaeyama, and possibly Yonaguni), attempts have also been made to establish a genetic relationship between Japanese and various other language families. Most of these attempts have been amateurish, a major exception being the Koreo-Japonic hypothesis, which still remains unproven as well. It is also quite likely that the Japonic language family (or, more precisely, Insular Japonic) is the only linguistic grouping whose genetic relationship can be established beyond any doubt. A genetic relationship is also likely to exist between Japonic and a number of fragmentarily attested languages that once flourished in the south and center of the Korean Peninsula, but that died out no later than 9th century A.D. The paucity of material available does not allow one to establish solid predictive-productive regular correspondences in many cases, but intuitively the genetic relationship seems to be a matter of fact. Anything beyond intuition, however, lies in the realm of conjecture and speculation. The alleged Koreo-Japonic relationship is best explained by a centuries-long contact relationship rather than by common origin, given such factors as the virtual absence of any kind of shared paradigmatic morphology, as well as by multiple problems in establishing the real (and not imaginable or made-to-fit) regular correspondences. The Japanese-“Altaic” hypothesis is even more speculative and far-fetched. Consequently, the conclusion is that the Japanese language or the Japonic language family has no demonstrable relationship with any other language family or language isolate on the planet.