1. Know that most nouns derived from doubled roots come with the loss of one of the doubled letters, in the same manner as verbs of doubled roots. As a result, only two letters remain, such as dal, tal, sal, taf. Most of these are vocalized with pataḥ, while some are vocalized with a qamats, as determined by tradition. Many are also found with a ḥolam, such as oz, ḥom, ol, qor, and others with a tsere, such as ḥen, shen, tsel. All those with a qamats and a tsere follow the same patterns of inflection as nouns with a quiescent middle letter (nḥei ayin) and those with a quiescent final letter (nḥei lamed), as I have already shown you in their respective weights and governing principles.

2. And I will give you a sign by which you may recognize which nouns belong to the class of those with a quiescent middle letter (nḥei ayin), which to those with a quiescent final letter (nḥei lamed), and which to the doubled roots. This is the rule: nouns of doubled roots ought, by their nature, to appear with a dagesh, in order to indicate the doubling of the two identical letters. However, it is impossible to place a dagesh forte on one of them when it stands at the beginning of a word, since a dagesh forte never occurs at the beginning of a word. This will be explained to you in the chapter on Shirah, in Song Eight.

And at the end of a word a dagesh can never occur. Therefore, when you encounter a noun consisting of only two letters and you do not know to which class it belongs, you may test it in the following way: If it is capable of receiving a dagesh in its pronominal suffixes, or in its plural forms, or when combined with the feminine he, then it belongs to the class of doubled roots.

3. And the example is from zakh. If you wish to know from which class it comes, place at its end a letter of plurality, or of a pronominal suffix, or the feminine he, and you will find: zakkim, zakkav, zakkah. All of these take a dagesh; therefore they belong to the class of doubled roots. And from ḥag you say ḥaggim, ḥaggo; all with a dagesh, so they too are from the doubled class. But from dag you say dagim, dagah, with the gimel remaining soft. Therefore it is from the class of quiescent roots. And I have already given you a sign in this treatise, in the Eighth Principle, by which you may distinguish quiescent middle-letter roots from quiescent final-letter roots. I explained there that quiescent middle-letter roots never change their vowel. Thus, since you say dagim, dege ha-yam (“the fish of the sea”), where the qamats changes to a sheva, it follows that it is from the class of quiescent final-letter roots, and its root is gadah. But from ger you say gerim, garu, and the tsere does not change. Therefore it belongs to the class of quiescent middle-letter roots, and its root is gur.

5. And the general rule is this: Every noun that you find consisting of two root letters, where the second letter appears in the plural, in pronominal suffixes, and in the feminine form, belongs to the class of doubled roots. Such nouns always have one of the short vowels at the beginning. Even those that are pointed with a qamats according to the tradition—such as yam (“sea”) in “the Salt Sea” (Genesis 14:3), or tam (“perfect”) in “perfect and upright” (Job 1:1), and the like—when they appear in the plural, with suffixes, or with the feminine ending, they become a pataḥ-vocalized, as in temimim, temah. Those with a tsere appear with a ḥiriq, such as shen → shino, ḥen → ḥano. Those with a ḥolem appear with three vowels, as from ḥoq: ḥuqqo, ḥuqqai, ḥuqqam. And when the middle radical is pointed with a sheva, then the first radical takes a ḥatef-qamats, as in “You guided them in Your strength” (Exodus 15:13), and likewise ḥuqqekha, ḥuqqekhem, as Rashi explained on “my strength and song is Yah” (Exodus 15:2). However, Rabbi Abraham ibn Ezra rightly challenged him there—see his commentary.