Thomsen, Vilhelm (vĭlˈhĕlm tŏmˈsĕn) [key], 1842–1927, Danish philologist. For many years Thomsen was professor of comparative philology at the Univ. of Copenhagen, where he did important work in Indo-European linguistics. His best-known work was the decipherment of the bilingual Turkic-Chinese inscription found on the Orkhon River in Mongolia. The inscription, published in 1894, is in the most ancient form of Turkish yet found.