Derhotacization vs. Rhotacism — What's the Difference?

A distortion in (or an Inability to pronounce) the sound of letter R, causing the R to be omitted as a consonant or changing /ɝ/ or /ɚ/ to /ɜ/,/ə/, or another vowel if a vocalic.

The change of a sound such as (s) or (z) to (r) in the history of a language, such as the change of Proto-Indo-European intervocalic s to r in Latin, resulting in alternations such as that seen between the singular noun genus, "kind, sort" and its plural, genera. Also called rhoticism.

The inability to articulate the (r) sound as a rhotic consonant.

The substitution of the (r) sound with another sound, such as (w), because of this inability.

The articulation of a sound other than (r) as (r), especially the articulation of (z) as (r).

An exaggerated use of the sound of the letter R.

A linguistic phenomenon in which a consonant changes into an R, such as Latin flos becoming florem in the accusative case; rhotacization.

Inability to pronounce the letter R; derhotacization.

An oversounding, or a misuse, of the letter r; specifically (Phylol.), the tendency, exhibited in the Indo-European languages, to change s to r, as wese to were.