Strong and weak roots. § 57. The large majority of all Semitic words, as is well known, are derived from roots which for the most part have three, but occasionally even four or more 'Radicals'. If the three radicals are firm consonants, the roots are then called Strong: but if one of the radicals is ܘ or ܝ (frequently appearing as a vowel), or if the due weight of the word is attained by the doubling of one of two firm radicals, then the roots are called Weak. On practical grounds we retain this method of treating roots, without insisting farther on the point that even with strong roots a radical is often demonstrably of quite recent origin, while on the other hand there is much variety in the origin of weak forms of the root, and while in many cases at least, the assumption of an original Waw or Yod as a radical, or that of a third radical with the same sound as the second, is a pure fiction. Thus we speak of roots primae ܘ or ܝ (פו׳, פי׳) [Pe Waw, Pe Yod] meaning those whose first radical is taken as W or Y; so of roots mediae ܘ or ܝ (עו׳, עי׳) [Ayin Waw, Ayin Yod], and tertiae ܝ and mediae geminatae (עע׳) [Lamed Yod, and Ayin doubled]. In addition we have frequently to deal specially with words of which ܐ is a radical; for this sound (cf. § 33 sqq.) undergoes many modifications. In like manner we have to treat of words which have n as the first letter of the root. The forms too, which have a guttural or an r as second or third radical, are, by reason of certain properties, brought occasionally into special notice.