1. Know that there are nouns from this class that appear without any added letter and consist of only two letters. The first radical is always pointed with one of the five “major” vowels: with qamats, as in zar, tsar, raʿ; with tsere, as in ger, tsad, ʿad; with ḥiriq, as in sir, qir, ʿir; with ḥolam, as in or, yom, tov; and with shuruk, as in shur and dor.

2. But they are not found with the minor vowels. Most of them do not undergo any change, and those that do change do so in different ways. For example, from yom (“day”) the plural and its pronominal forms come with a qamats, as in yamim, yamav, and so forth. Likewise from rosh (“head”) come rashim, rashav. Apart from these, there are no others.

And tov (“good”) comes in the construct state and with pronominal suffixes in shuruq, as in tov, tovo, and the like—this is when it is a noun. But when it is an adjective, it does not change. See the roots in the work of Rabbi David Kimhi.

3. And those with a qamats or a tsere do not change at all, and the reason for this will be explained to you in this treatise, Principle Eight. Likewise, those with a ḥiriq or a shuruq mostly do not change. The exceptions are as follows: ʿir (“city”) forms its plural with a mobile yod, as in ʿirim and ʿirot; shoq (“leg” or “thigh”) forms its plural with a mobile vav, shoqim; and from qots (“lock of hair”) comes qotsotav. Likewise, from dud (“pot”) we find the forms sirōt and dudim.

4. There are also cases in which a mobile yod appears in singular, such as bayit (“house”), ʿayin (“eye”), zayit (“olive”), layil (“night”), ḥayil (“strength”), and ʿir (“city”). All of these are accented on the penultimate syllable; were this not so, the yod would have to be doubled, as is the rule after a short vowel. In all four types of inflection, the yod becomes quiescent with a tsere, as in bayit, bayto; zayit, zayto, zaytim; layil, laylo, leilot; ayil, ayilim; ḥayil, ḥaylo. The plural with a mobile yod also appears in the plural form ḥayilim. Likewise, from ʿir comes ʿirim, and the pronominal form is ʿiro, with ḥiriq. The word batim (“houses”) is very exceptional, in that it has a doubled consonant after a long vowel and is accented on the final syllable.

5. Some are also found with a mobile vav in the singular, such as ʾaven, ʿol, mavet, and tokh, with qamats or segol; and there is no corresponding pattern for them among the regular (strong) roots, as I explained in the Third Treatise, Second Principle, Seventh Section. In the construct state and with pronominal suffixes the vav usually becomes quiescent, as in betokh ha-ʿir (“in the midst of the city,” Gen. 18:24) and mot yesharim (“the death of the upright,” Num. 23:10). Likewise with suffixes: lifnei moto (“before his death,” Deut. 33:1), el tokho (“into its midst,” Lev. 21:33), mehashiv ʾonekh (“from turning away your iniquity,” Jer. 4:14). When a final he is added, the vav remains mobile, as in motah ʿolah; and another example is found with a mobile vav before a suffix: beʿolah asher ʿasah (“in the trespass that he committed,” Ezek. 18:26). The form sheva also belongs to this pattern, but the segol was lightened and changed into a sheva because of the weakness of the aleph, whose regular vowel is sheva.