Gesenius' Hebrew Grammar/92. Vowel Changes in the Noun
92a 1. Vowel changes in the noun may be caused (a) by dependence on a following genitive, (b) by connexion with pronominal suffixes, (c) by the plural and dual terminations, whether in the form of the absolute state or of the construct (before a following genitive of a noun or suffix).
92b 2. In all these cases, the tone of the noun is moved forward either one or two syllables, while the tone of the construct state may even be thrown upon the following word. In this way the following changes may arise:—
(a) When the tone is moved forward only one place, as is the case when the plural and dual endings ־ִים, וֹת and ־ַ֫ יִם are affixed, as well as with all monosyllabic or paroxytone suffixes, then in dissyllabic nouns the originally short vowel of the first syllable (which was lengthened as being in an open syllable before the tone) becomes Šewâ, since it no longer stands before the tone. On the other hand, the originally short, but tone-lengthened vowel, of the second syllable is retained as being now the pretonic vowel; e.g. דָּבָר word (ground-form dăbăr), plur. דְּבָרִים; with a light suffix beginning with a vowel, דְּבָרִי, דְּבָרֵ֫נוּ; plur. דְּבָרַי, דְּבָרֶ֫יךָ, &c.; בָּנָף wing, dual כְּנָפַ֫יִם. With an unchangeable vowel in the second syllable: פָּקִיד overseer, plur. פְּקִידִים; with the suffix of the sing. פְּקִידִי, פְּקִירֵ֫נוּ, &c.; with the suff. of the plur. פְּקִידַי, פְּקִידֶ֫יךָ, &c. With an unchangeable vowel in the first syllable: עוֹלָם eternity, plur. עֽוֹלָמִים, with suff. עֽוֹלָמִי, &c.
92c But in participles of the form קֹטֵל, with tone-lengthened ē (originally ĭ) in the second syllable, the ē regularly becomes Šewâ mobile before a tone-bearing affix, e.g. אֹיֵב enemy, plur. אֹֽיְבִים, with suff. אֹֽיְבִי, &c. Likewise in words of the form קִטֵּל, קַטֵּל, &c. (with ē in the second syllable; §84bd, l, p; §85i and k), e.g. אִלֵּם dumb, plur. אִלְּמִים.
92d (b) When the tone of the construct state, plural or dual, is carried over to the following word, or, in consequence of the addition of the grave suffixes to the constr. st. plur. or dual, is moved forward two places within the word itself, in such cases the originally short vowel of the second syllable becomes Šewâ, while the vowel of the first syllable reverts to its original shortness, e.g. דִּבְרֵי הָעָם the words of the people, דִּבְרֵיכֶ֫ם your words, דִּבְרֵיהֶ֫ם their words (in all which instances the ĭ of the first syllable is attenuated from an original ă). 92e In the segholate forms in the singular and mostly in the dual the suffix is appended to the ground-form (מַלְכִּי my king, מַלְכֵּ֫נוּ, &c.); on the other hand, before the endings ־ִים, וֹת (sometimes also before ־ַ֫ יִם) a Qames regularly occurs, before which the vowel of the first syllable then becomes vocal Šewâ (מְלָכִים, מְלָכוֹת). This Qameṣ (on which cf. §84aa) remains even before the light suffixes, when attached to the plur. masc. (מְלָכַי, מְלָכֶ֫יךָ, &c.). On the other hand, the constr. st. plur. and dual, regularly, according to d, has the form מַלְכֵי, with grave suffix מַלְכֵיכֶם, &c., דַּלְתֵי from דְּלָתַ֫יִם folding-doors.
92f (c) Before the Šewâ mobile which precedes the suffix ךָ when following a consonant, the a-sound, as a rule, is the only tone-lengthened vowel which remains in the final syllable (being now in an open syllable before the tone), e.g. דָּֽמְךָ֫, דְּבָֽרְךָ֫, &c. (on the forms with ē in the second syllable, see §93qq); but before the grave suffixes ־ְכֶם and ־ְכֶן in the same position it reverts to its original shortness, as דְּבַרְכֶם (debhărkhèm), &c. In the same way the tone-lengthened ā or ē of the second syllable in the constr. st. sing. also becomes short again, since the constr. st. resigns the principal tone to the fenowing word, e.g. דְּבַר אֱלֹהִים; חֲצַר הַבַּ֫יִת (from חָצֵר).
92g Rem. The Masora (cf. Diqduqe ha-ṭeamim, p. 37) reckons thirteen words which retain Qameṣ in the constr. st., some of which had originally â and therefore need not be considered. On the other hand, אוּלָם or אֻלָם 1 K 76, Ez 4048, &c. (in spite of the constr. st. plur. אֻֽלַמֵּי); מִבְטָח ψ 656, Pr 2519; מַצָּב 1 S 1323 (so Baer, but ed. Mant., Ginsburg, &c. מַצַּב); מִשְׁקָל Ezr 830 and מַתָּן Pr 1816 are very peculiar.
92h 3. The vowel changes in the inflexion of feminine nouns (§ 95) are not so considerable, since generally in the formation of the feminine either the original vowels have been retained, or they have already become Šewâ.
92i Besides the vowel changes discussed above in a–g, which take place according to the general formative laws (§§ 25–28), certain further phenomena must also be considered in the inflexion of nouns, an accurate knowledge of which requires in each case an investigation of the original form of the words in question (see §§ 84–86). Such are, e.g., the rejection of the ה of ל״ה stems before all formative additions (cf. §91d), the sharpening of the final consonant of ע״ע stems in such cases as חֹק, חֻקִּי, &c.
92k A striking difference between the vowel changes in the verb and noun is that in a verb when terminations are added it is mostly the second of two changeable vowels which becomes Šewâ (קָטַל, קָֽטְלָה, קָֽטְלוּ), but in a noun, the first (דָּבָר, דְּבָרִי, דְּבָרִים), cf. § 27. 3.