goropism

From Johannes Goropius Becanus, who proposed a theory according to which Brabantic, a Dutch dialect, was the language spoken in Paradise, +‎ -ism.

goropism (usually uncountable, plural goropisms)

1. A theory that some modern or attested language, such as Dutch, Turkish, or Hebrew, was the original language of mankind.
2. An absurd etymology proposed as part of such a theory.

• folk etymology