rhotacize
/ˈrəʊtəsʌɪz/(also rhotacise) Linguistics
verb
1 [with object] To change (a sound, especially the phoneme/s/) into the phoneme/r/. Also: to alter the form and pronunciation of (a word) by changing one of its sounds, especially the phoneme/s/, into the phoneme/r/.
2 [no object] Of a sound (especially the phoneme/s/): to change into the phoneme/r/.
Origin
Late 19th century. Either from Byzantine Greek ῥωτακίζειν to make overmuch or wrong use of the letter ῥ (from ancient Greek ῥῶ + -ίζειν, with inserted -τακ- probably after Hellenistic Greek ἰωτακισμός), or independently from rhotac- + -ize.