The Hungarian language belongs to the Ugric branch of the Finno-Ugric stock; it is therefore not related to Germanic, Slavic, or any other Indo-European language. The only other national language in Europe of the Finno-Ugric stock is Finnish. Hungarian is more closely related, however, to the other languages of the Ugric division, namely Vogulian and Ostjak, spoken by tribes in the Ob and Irtis regions of northwestern Siberia. Further relationship of the Finno-Ugric stock to the languages of the Samojed group, forming an ‘Ural’ stock, and of the ‘Ural’ stock thus formed to the ‘Altaic’ languages (the Turkish, Mongolian, and Manchu-tung groups), and possibly to Japanese, thus forming a great ‘Ural-Altaic’ family, has been postulated, but it is not regarded as definitely proven.