Derhotacization vs. Rhotacism

Derhotacizationnoun

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.

Rhotacismnoun

An exaggerated use of the sound of the letter R.

Rhotacismnoun

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

Rhotacismnoun

Inability to pronounce the letter R; derhotacization.

Rhotacismnoun

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.