It was first posited in 1896 and published in 1898 by Rudolf Thurneysen,[citation needed] a comparative linguist more famous for his work on the Celtic branch of Indo-European and in particular for his Handbuch des Altirischen.
[citation needed] For example, the abstracting suffix -umni- is represented both as -ubni (fastubni, fraistubni, witubni) and as -ufni (waldufni, wundufni).
Many text- and handbooks choose to completely ignore it, or to pass over it with only slight mention, and it remains among the lesser known sound laws of Germanic philology.
In 1968, Noam Chomsky and Morris Halle published a new and somewhat less sensitive form of Thurneysen's law in modern notation.
This version lacks Thurneysen's rules about consonantal clusters, and his observations on the effects of liquids.