As with any mantra, knowledge of right pronunciation and meaning of words is helpful for the fullness of the effect of Savitri. For that matter the rhythm is even more important and that depends more on the right pauses and intonation than pronunciation alone.
However if this were a precondition, then very few, including many English-speaking readers, would qualify to read it. What is much more important is to read a little every day, to read slowly and with sufficient quietude and then meditate upon the lines that have been read.
Also it is essential to read Savitri with a faith and aspiration in the heart, knowing that it is the Word-body of Sri Aurobindo, a living reality draped in word and sound. If one does it with sufficient faith then the rhythm begins to emerge from within and the mantric power works bypassing all the rules and canons of reading.
If one wants to know how to read Savitri it is best to listen to the Mother’s reading which is available on this website.