Farsi / Persian / Dari
Except for two additional characters in the Persian (aka Farsi), Dari and Persian are the same in these translations of May Peace Prevail on Earth.
Persian is the official language of Iran where it usually is called Farsi. Two versions of it known as Dari and Tajik are among the official languages in Afghanistan and Tajikistan (although Tajik has a different alphabet). In all three of those countries those are the languages of Islamic liturgy.
It is spoken by 110 million people.