Rhombencephalic isthmus

What is Rhombencephalic isthmus?

Rhombencephalic isthmus definition and meaning on Dictionary terms:
Historical Linguistics. a change of a speech sound, especially (s), to (r), as in the change from Old Latin lases to Latin lares.
excessive use of the sound (r), its misarticulation, or the substitution of another sound for it.


reference: https://www.dictionary.com/browse/rhombencephalic-isthmus