[a] 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).
[b] 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.[1]
[c] 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; § 84b d, l, p; § 85 i and k), e.g. אִלֵּם dumb, plur. אִלְּמִים.
[d] (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).