I actually had the opportunity to talk with the VA who played Jul 'Mdama. The Sangheili language is loosely based off of Japanese, using a similar grammar structure and sound. Originally, the Elite VAs were supposed to mess around with Japanese words to create their own lines of dialogue. That is until 343i came to them with a script. (Leads me to believe 343i actually has/made a Sangheili dictionary) I find the influence from the Japanese language incredibly appropriate since the Elites were heavily based off of Feudal Japan in the first place.