Why is the Altaic hypothesis about Korean controversial among linguists?

The Altaic hypothesis, which suggests that Korean shares a genetic relationship with the Altaic languages—a group typically comprising Turkic, Mongolic, and Manchu-Tungus languages—remains a subject of significant debate among linguists.12

The controversy stems from the difficulty of proving a common ancestral origin. While some scholars point to structural similarities and shared vocabulary as evidence of a genetic link, many others argue that these commonalities are not definitive proof. Critics often attribute these resemblances to "areal convergence"—the result of prolonged geographic proximity and mutual borrowing—rather than a shared linguistic lineage.12

Because reliable, systematic sound correspondences have not been universally demonstrated to the satisfaction of the broader linguistic community, the hypothesis has not achieved general acceptance. Consequently, while some researchers continue to investigate the potential connection, most scholars now reject the idea of a genetic family, though many acknowledge that the Altaic category remains useful for studying the shared features that emerged through historical contact.12