Linguists used to believe that languages like Japanese, Korean, Mongolian, Turkish, and Finnish were part of the Altaic language family. This was because of similar features like SVO (subject-verb-object) word order and agglutinating grammar. However, most linguists no longer believe that the Altaic language family ever existed. The languages became more similar over time, whereas most related languages become more different over time. It is possible that these languages are part of a sprachbund.