a plural morpheme takes on is determined by the following morphological rules: Assume that the basic form of the plural morpheme, /z/, is [z] ("bags" /bægz/) The morpheme /z/ becomes [əz] by inserting an [ə] before [z] when a noun ends in a sibilant ("buses" /bʌsəz/) Change the morpheme /z/ to a voiceless [s] when a noun ends in a voiceless sound ("caps" /kæps/) Negative allomorphs In English, the negative prefix in has three allomorphs: [ɪn], [ɪŋ], and [ɪm]. The phonetic form that the negative morpheme /ɪn/ uses is determined by the following morphological rules: the negative morpheme /ɪn/ becomes [ɪn] when preceding an alveolar consonant ("intolerant"/ɪn'tɔlərənt/) the morpheme /ɪn/ becomes [ɪŋ] before a velar consonant ("incongruous" /ɪŋ'kɔŋgruəs/) the morpheme /ɪn/ becomes [ɪm] before a bilabial consonant ("improper" /ɪm'prɔpər/) In Sami languages The Sami languages have a trochaic pattern of alternating stressed and unstressed syllables. The vowels and consonants that are allowed in an unstressed syllable differ from those that are allowed in a stressed syllable. Consequently, every suffix and inflectional ending has two forms, and the form that is used depends on the stress pattern of the word to which it is attached. For example, Northern Sami has the causative verb suffix -hit/-ahttit in which -hit is selected when it would be the third syllable (and the preceding verb has two syllables), and -ahttit is selected when it would be the third and the fourth syllables (and the preceding verb has three syllables): goarru-t has two syllables and so when suffixed, the result is goaru-hi-t. nanosm-it has three syllables and so when suffixed, the result is nanosm-ahtti-t. The same applies to inflectional patterns in the Sami languages as well, which are divided into even stems and odd stems. Stem allomorphy Allomorphy can also exist in stems or roots, as in Classical Sanskrit: There are three allomorphs of the stem, , , and , which are conditioned by the particular case-marking suffixes. The form of the stem , found in the nominative singular and locative plural, is the etymological form of the morpheme. Pre-Indic palatalization of velars resulted in the variant form , which was initially phonologically conditioned. The conditioning can still be seen in the locative singular form for which the is followed by the high front vowel . However, the subsequent merging of and into made the alternation unpredictable on phonetic grounds in the genitive case (both singular