Language of the elf-like people? This anime is still fairly new so I may be jumping the gun a bit, but in the episodes so far the people living in the world that the protagonist Toyohisa was transported to don't appear to speak Japanese. 

Now my assumption may be off as I am not a fluent speaker, but as a third semester Japanese minor I usually can pick up on some words, phrases and contexts without looking at the subtitles. 

When the elves speak there is a clear change in tone, pitch and pronunciation of words.

Are they speaking a different language entirely? Or just some sort of abbreviated form?
The language is officially called &quot;Orte&quot;, based on &quot;Orte Empire&quot;.
In the original manga, it appears only in written form with Japanese translation (no transliteration/spoken form). The character looks like a random scribble (and even like this...), but later was thought to be a modified Japanese hiragana &amp; katakana.


Transliteration:
げきぶ
どりふたあず
がくにを
もしわれ
さんどうする
のならゆみ
をとりやを
つがえ
From 佐とさん's Twitter

When Drifters got animated, Kouta Hirano (the author) didn't think about it at all. He mentioned it on the Twitter,

The incoherent character that I wrote randomly on the spot, known as Orte language, was adjusted to be a fictional Latin-based language by the anime staffs. I can only say sorry while dogeza-ing with my head thrusting the ground.

Seiichi Shirato, a setting researcher for Drifters, also mentioned about the difficulty in dialog speech due to Orte language. From his interview,

What's the most memorable impression when doing researches for Drifters?
The problematic one is about the dialog speech. Regarding the Orte language that is spoken by the elfs, there's a conversation to just reverse the Japanese text/dialog. When we tried it, apparently it's still similar to Japanese, thus we created a language based in Europe. There's an idea to modify Latin little by little, but since Scipio (a character in Drifters) speaks Latin, he would find out!

Surprisingly, Orte language seems to have its own language structure. A Japanese blogger tried to analyze the language, though it ended only until episode 3.
Examples:


seda- : stop (verb)
neruc- : kill (verb)
quinacos: what (intransitive)
quinacom: what (transitive)
tu: you (2nd-person pronoun)
hi/hii: he (3rd-person pronoun)