Never heard of him, this
Lambert ten Kate, Dutch philologist and archaeologist. (Thanks for the enlightenment, Bran.) I have heard of another famous Dutch linguist, Johannes Goropius Becanus [1519-1572] (
link) who "theorized that Antwerpian Flemish, or Brabantic, spoken in the region between the Scheldt and Meuse Rivers, was the original language spoken in Paradise".
Though Goropius had admirers (among them Abraham Ortelius and Richard Hakluyt), his etymologies have been considered "linguistic chauvinism," and Leibniz coined the term "goropism" to mean "absurd etymology." Justus Lipsius and Hugo Grotius discounted Goropius’ linguistic theories. "Never have I read greater nonsense," the scholar Joseph Scaliger wrote of Goropius' etymologies.
One meets some modern day Goropian language enthsuiasts on the boards these days. Another, and more famous, Dutch linguist I know of is Hendrik Poutsma, who wrote a wonderful grammar of English (see
link for volume one of five digitized). Two of the best 20th century grammars of English were written by non-native speakers of English (the other grammarian is Otto Jespersen), though the Dutch and the Danes hold their own when it comes to learning other languages.
Ablaut and its younger sibling,
umlaut, are types of
apophony (
link).