Dear Amir, I think your interest in Middle Persian or Pahlavi is very commendable but unfortunately the Pahlavi script, which is based off of a modified Aramaic script, is ill suited for any modern language. In Pahlavi, a person would write one word as it was written in Aramaic and pronounce it completely differently. Take for example the word "Malek" or king. The Sassanid Persians would write 'Malek" in Pahlavi but pronounce it as 'Shah". They did this probably for convenient communication purposes. Most people in the Empire probably spoke Aramaic as they did during the Achaemenid times and creating a brand new script was inefficient. Also, Pahlavi still does not represent most vowel sounds just like the Arabic script currently being used in Iran. Instead, most vowels were presumed in words.However, the Avestan script does represent vowels and is originally Indo-European.