The /n/ is an original consonant in Hebrew and Arabic, and comparative linguistic studies confirm its originality in all Semitic languages. Due to the importance of the /n/ in the vocal structure of the Arabic word, the Quranic literature allocated chapters to study its rules. But the importance of this consonant is not restricted to phonetics only. We have found that it has effects on the linguistic and grammatical structure of the word in both Hebrew and Arabic. Therefore, our study aims to unveil the importance of this consonant and its role in the linguistic structure of the word in both languages. To achieve this we adopted the comparative linguistic approach.