A sample of 80 loanwords and 100 native Arabic words ending with /ya:t/ or /yya:t/ were analyzed and compared to find out the conditions under which /ya:t/ and /yya:t/ appear in Feminine Sound plural forms of those words. Results revealed that Arabic speakers pluralize native and loan nouns ending with the glide /y/, which is part of the words, as ناي/na:y/; & قبضاي /qabaDa:y/ (Turkish) by directly adding the feminine plural suffix /-a:t/ to the stem without making any other adaptations (نايات /na:ya:t/ flutes & قبضايات /qabadaya:t/ strong-arm). In native words with a stem ending in the graphemes ى or ي pronounced /a:/ and /i:/, the vowel is shortened and the glide /y/ is added as a liaison consonant as inتمنيات /tmanniya:t/ wishes; مديات /maday:at/ ranges). When the loan stem ends in the syllable يا /ya:/, the final long vowel /a:/ is deleted before the plural suffix /-a:t/ as Arabic phonotactics do not allow a sequence of two long vowels as in بكالوريا /bakalo:rya/ > بكالوريات /bakalory+a:t/ high school diplomas. A geminated glide /yy/ appears in the plural of native words as أدبيات /?adabiyy+a:t/ literature; برمجيات /barmadʒiyy+a:t/ software) and plural loanwords as سيديات /si:di:yy+a:t/ CD’s; سيلفيات selfies /selfiyy+a:t/; باربيات /ba:rbi:ya:t/ Barbies; سمفونيات /simfo:ni: +y+a:t/ symphonies. In these examples, there are two explanations of the stem: One assumes that the masculine singular stem ends in a geminated yy, after which the plural suffix /a:t/ is directly added. The second assumes that the stem is a feminine singular noun/adjective ending in a geminated yy followed by the grapheme ta marbouta ة ــة pronounced /a/. /a/ is deleted when the plural suffix /a:t/ is added, as Arabic does not allow the sequence of two vowels. The vowel preceding the geminate yy is shortened in the plural form of native and loanwords in Arabic. The study gives some recommendations for translation and pedagogy and for future studies on Arabic loanword morphology.