The language of the Elysians is Seraphim.
Strictly speaking Serpahim is a descendant of Latin, however it has changed enormously over the centuries absorbing features and words from other languages (most notably Greek, Italian and Hebrew) to the stage where the two languages are barely recognisable as related. It has a decidedly angelic feel, angelic and vaguely arcane.
The grammar and sentence structure of Seraphim are primarily those of Latin, and many of the verbs and nouns are a mutated version of Latin and Greek. That being said these words aren’t really recognisable – it is a little like comparing an English word to Sanskrit. The general feel of the language remains a mixture between Greek and Latin. The grammar is notably complex – it is a particularly hard language to learn, meaning that few non-Elysians do – but this means that it leans itself to subtlety and there is a complex system of power within words. Double meanings are particularly common.
How the language developed is unknown. The Elysians themselves believe it simply grew out of Old Seraphim and that it is there natural language. Several Elysian academics have developed rather complex theories about how Latin, Greek, Hebrew and indeed most other languages have evolved from Seraphim – rather than the other way around. The evidence behind this is minimal, but national pride demands it. It should be noted, however, that there is an element in Seraphim which is completely alien and unrelated to human languages – exactly where this came from is unknown.
As with most things in Elysian society it is a source of great pride, and loan words are now resisted with great ferocity. Most Patriarchs speak English and Japanese, and a Plebeian who does not speak English is seen as a little ill educated, but it is seen as a rather uncouth thing to speak any tongue other than Seraphim. Certainly littering your language with English or Japanese words is almost grounds for social exclusion. They are widely seen as the uncivilized tongues of uncivilized races – useful for communicating with them but for little else.
Seraphim evolved out of ‘Old Seraphim’, which is far more closely related to Latin and Greek, enough for a Latin and Greek scholar to be able to translate much of the basic language – given enough time. However many of the more complex features and words are alien, and no-one knows from where it came. Fluency in Old Seraphim is something only found in some Patricians, usually academics, and it is usually only used to create impressive sounding names.