«فالتنافر: وصف في الكلام، يوجب ثقله على اللسان، وعسر النطق به»
Discord among words is a property of an utterance that makes it heavy on the tongue and difficult to pronounce.
Discord among letters belongs inside a single word, while discord among words concerns movement from one word to the next and their combined sound pattern.
Thus every word may be individually acceptable, yet their sequence may hinder fluent articulation. This distinguishes the defect from semantic obscurity or irregular morphology in an individual word.