The Impact of the Number of Vowel on the Area of Persian Vowel space in Learning German vowels based on Adaptive Theory Dispersion.

In this paper, the validity of a key prediction theory of adaptive dispersion theory on systematizing vowels is investigated. Based on that, the more the number of vowels in a vowel system, the larger the area of the acoustic space to create a perceptual distinction between vowels. This means that languages with more vowels take up more vowel space. To test this hypothesis, the frequency of the first and second constructs of the vowels shared in Persian and German languages produced by Persian-speaking German learners in the context of CV:CC, and the area of the vowel space of Persian and German languages produced by Persian-speaking German learners at three levels of basic, intermediate and advanced in the group of male and female are reviewed. This study utilized the Paget and Tabain method (2005) and Becker-Crystal area indices (2010) between the number of vowels and the area of vowel space using R software and PBS mapping package, and showed that there is a direct positive relationship, and the area of vowel space in females in advanced Persian-speaking German students is larger. This theory was confirmed in this group; while in other groups (Basic and intermediate) in females and males in all groups (basic, intermediate and advanced) this principle of theory was not corroborated.Keywords: Vowel space, Vowel tension, Vowel space area, German language, Persian language, adaptive dispersion theory