neogrammarian

/N IY0 OW0 G R AE1 M ER0 IY1 AH0 N/
noun
  1. 1

    A member of a 19th-century school of German linguists who first advanced the theory of regular sound change; or a follower of that school.

Source: https://en.wiktionary.org/wiki/Neogrammarian, https://en.wiktionary.org/wiki/neogrammarian