Russian historian Alexandre Nemirovsky proposed a hypothesis that Classical Black Speech was based on extinct Hurrian language. This idea is controversial but it became popular among Black Speech researchers.

1. We don't know for sure if J.R.R. Tolkien was familiar with E.A. Speiser's “Introduction to Hurrian” (1941), the first dedicated book on the subject.

• Original Russian text of hypothesis (Archive)
• Orkish and the Black Speech at Ardalambion. See “APPENDIX: Was the Black Speech based on Hittite/Hurrian?”.