The following is from a series titled "What is Prayers" on Frashogard.com written by our godo friend Ervad Marzban Hathiram,

Of the many gifts given to Parsis by their Prophet Zarathushtra, that of the Manthras is one of the most significant. Manthras are the divine words of the Prophet and His appointed disciples which form what we loosely call today the ‘Avesta’. Over the thousands of years that have passed since the time of the advent of Zarathushtra, the great majority of the Manthras have been, unfortunately, lost. What we have left is not more than 5% of the original, which are used for daily prayers as well as the rituals which form the core of the faith. The question is often asked: What is the use of praying in a language we do not understand? Cannot the same prayers be translated in to a common language like English and the same said with more concentration and meaning? Would it not be better if some newer and shorter prayers were introduced? In order to answer these and related queries, it is necessary to firstly understand who man is, what is his role in nature, what is prayer, why does man need to pray and what benefits accrue from praying.

Continue reading the entire article here.

UPDATE:

Part 2. Part 3 and Part 4 of the series are up on Frashogard’s site.