Enchantress and Incubus always speak some other language to each other, which is translated with subtitles for the audience. Is this a real language? A constructed language? Random gibberish with subtitles?
The actor who portrayed Incubus, Alain Chanoine, has said that the language ("moonspeak") was invented for the film by David Ayer. It bears little relation to any actual language and was written down fo-net-ick-al-ee for them to say.
NR: What language were you speaking in the voiceovers for Incubus?
AC: Moonspeak is the language. That’s the 4th language I speak now!
TMN: How did you and Cara Delevingne master speaking in your ancient character's dialect?
Chanoine: First, it was complicated because David wrote the thing down, we got to change it. I speak three different languages: Creole, French, and English. He wanted me to get more of my tone in the movie. And Cara, because she's British, she was speaking in a different way than I was, just because he wanted it to sound original to ourselves. So I got to change a lot of the Moonspeak and he was really open. So yeah, it was fun. It was fun to make it up with him. I don't get all the vocabulary he's using, but it was fun to play with that.
Apparently it was invented by the film's sound department using a technique of substituting nonsense words for the mouth-sounds made when the lines were read in English and using ADR to dub them back into the film.
Suicide Squad presented several unique challenges, Bach says, not the least of which was a late-breaking decision to have two characters speak in their own language — meaning dialogue originally filmed in English needed to be replaced with this new language that the sound crew dubbed “moonspeak.” The solution? “Reversing and slowing the picture down, transcribing phonetically, and substituting various syllables according to their mouth shape,” Bach says, adding that Berklee helped prepare him with the problem-solving skills to tackle a challenge like that. “I’ll never forget Dave Moulton’s first problem- solving class,” he says. “He handed us a black box with some connectors on it and asked us to draw a flow chart diagram of how it worked…I use that kind of logic—or try to—daily.”