This research includes both the short and the long vowels in the Arabic language for both the ancient and modern linguists and how to deal with these two forms described as phonemes that can change the meaning. The ancient linguists mixed up in describing them. They usually gave them the same definition although there is an acoustic and phonological difference .between them .This mixing up let to wrong explanation for morphological analysis vowels are considered the main centre in the linguistic. But this part was neglected by the ancient linguistic except which was serving the linguistic .structure