All phenomena arc constantly changing and language is not an exception. This change in. different aspects of language particularly, lcxis and sentences is more tangible. Due lo many reasons these changes occur beyond the scope of the present article. "Economy" in language is one of the most salient factors contributing to changes. Vowel shortening in the Persian language is one of those categories concerned with changes in lexical items in language. Vowel shortening can not be considered as an exception to linguistic rules Although nor much has been written on this issue. Thus. this article attempts to both clarify and look for the rules describing the process of shortening in /a:l/i:/ and U among the ? vowels as well as txlJe! and among the short ones.
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