182. Weak Roots in general. While, in a sense, all roots containing any unstable radical could be described as “weak”, we use the term here in the restricted connotation of those roots having w or y as their third radical. In some ways their behaviour parallels that of Hollow Roots; at times, however, the Weak Roots are considerably more complex and diverse; in at least one respect, namely the lack of any distinction between w and y roots in the Derived Forms, they are rather simpler than the Hollow Roots to learn and remember. Once again, the basic operative principle is that a syllable in Arabic cannot normally be both long and closed. Perhaps the most obvious characteristic of the Weak Roots is a tendency, where the weak radical is retained, to make diphthongs.

183. Weak Roots: Māḍī of I. As with the Hollow Verbs, there are in Form I two major categories, divided according to the exact nature of the final radical as w or y; and a third, minor category that may have either radical originally, but displays only y, and that with a fixed, deviant vowel-pattern. We give below the three categories set out at length for the three verbs da'ā (D'W), “to call” (and many shades of meaning, with different prepositions relating to “invitation”, “prayer”, “blessing” and “cursing”); ramà (RMY), “to throw, aim, pelt”; and raḍiya (RḌW), “to accept, be tolerant, indulgent” (of, towards: bi 'an and other constructions).