For Blanke, a planned language was essentially a tool: if it worked it was worthy of study and use; if it failed to work, he was interested in why, though at the same time careful to avoid value judgments. Blanke himself spoke a planned language, namely Esperanto, and recognised this language and language projects like it as arising out of a coherent theoretical base and addressing a recognisable problem. Essentially independently of the sociolinguistic school in the west, Blanke had reached a similar conclusion: if a language phenomenon exists, it is worthy of scholarly examination in itself. Blanke was particularly interested in how planned languages related to ethnic languages, how the 'artificiality' of, say, Esperanto extended to, indeed was synonymous with, the 'artfulness' of ethnic language, and how planned language could solve taxonomic and terminological problems. (Humphrey Tonkin)
Detlev Blanke (30 May 1941 – 20 August 2016) was a German interlinguistics lecturer at Humboldt University of Berlin. He was one of Germany's most active Esperanto philologists and was from 1991 to 2016 both the chair of the Gesellschaft für Interlinguistik ("Interlinguistics Society") and the editor of its newsletter, Interlinguistische Informationen. He earned a doctorate from Humboldt University of Berlin in 1976 with his dissertation on comparative word construction of Esperanto and German. In 1985 he earned a second doctorate from Humboldt on constructed languages.
He and his wife, Wera Blanke, were especially interested in the evolution of language, particularly in the development of terminology for the constructed language Esperanto and questions of sociolinguistics. Blanke studied Eugen Wüster's work toward common international terminology and international standardization.