9 letters · 16 points in Scrabble
originFrom New Latin rhōtacismus, from Ancient Greek *ῥωτακισμός (*rhōtakismós), from ῥωτακίζω (rhōtakízō, “to incorrectly use rho”), from ῥῶ (rhô, “rho (the Greek equivalent of r)”) in analogy with ἰωτακίζω (iōtakízō, “to incorrectly use iota”); itself from ἰῶτα (iôta) in analogy with ἀττικίζω (attikízō, “talk like an Athenian”). By surface analysis, rho + -tacism.
Etymology from Wiktionary, CC BY-SA 3.0