Persian has six vowels among which /u:/. /i:/ and /A:/ are long. The hiatus caused by adding the plural morpheme /-An/ to the nouns ending with /u:/ is resulved by the glide [w]. while the hiatus in nouns ending with /i:/ and /A:/ is resulved by the glide [j]. https://www.roneverhart.com/Field-Slacks-Mens-p10549/