Abstract: This study uses descriptive and diachronic approaches to explain the different levels of the articulated utterances in the medial position consonants of the Qur’anic readings and accounting for the short vowel insertion and vice versa. The researcher has studied the vowel insertion-deletion processes and provided evidence to see if this variation is due to sociolinguistic or just linguistic factors based upon a phonological analysis of word forms which are further investigated within the Qur’anic context. This study contains the introduction ،three chapters and a conclusion. The introduction chapter deals with the motivation for the vowel deletion in the medial position. Chapter two deals with the vowel deletion processes concerning three vowels /u/،/a/ and /i/ while the third chapter investigates the vowel insertion processes: /u/،/a/ and /i/ ،whereas the fourth chapter provides an analysis for the variation patterns observed at different levels : /i/ and/u/ ،/u/ and /a/ ،/a/and /i/. Results are shown and discussed in chapter four.