SPOILER ALERT: The following goes into detail (and shows part of) the main story and its ending.
Dirth ma, harellan. Ma banal enasalin. Mar solas ena mar din.
A conversation between the fear demon and Solas - or more formally, the Dread Wolf. The Trickster God. Fen'harel.
Dirth ma, harellan. Loose translation is Speak to me, Trickster. Tell, say. The root of the word "harel" means "to trick", whereas harellan acts as a noun.
Tell me, Trickster.
Ma banal enasalin. In literal words, "your nothing victory" or "your victory is nothing". A stranger way of putting it, however, is in light of the word "banalhan" which means the "place of nothing" - the Elven word for the origins of the Blight. Its meaning may be removed if the suffix -han is removed, but at the same time, it can also play on words with "nothing" as in the Blight as a victory. Pure conjecture, of course, but it has its undertones. Let's continue this later.
On a superficial level, Enasalin means both victory or emerging victorious. Enasal means "Joy in triumph over loss" where as "lin" usually means akin to the same blood. Whether literally sharing the same blood, or as compatriots. As Corypheus and Fen'harel were in cahoots with each other regarding the Orb, it is likely a translation with pale or false endearment between the demon and Fen'harel. A victory of nothing, as banal is placed before enasalin, and acts in possession or is grammatically linked together.
Tell me, Trickster. My victor is nothing. (Or: your victory is nothing)
Mar solas ena mar din. The first to note is that Solas is not capitalized in the subtitles. Therefore, solas in this context means "pride". Ena means to appear or emerge. Din means the dead. The noun "dead" or the deceased, NOT the verbage of being dead. As "ma" means my/mine/you and "ar" stands as "I" or "me", mar may be the formal or imperfect way of saying your.
Tell me, Trickster. My victor is nothing. (Or: your victory is nothing) Your pride emerges from your dead.
Solas returns with "Banal nadas." Banal as nothing, nadas as inevitability, or "something that must be." In other words, "Inevitability is nothing". Nadas is a noun, and the way this phrase is grammatically constructed, banal is a modifier of nadas. The same way the Inquisitor yells "Banal abelas" and "Banal vhenan" at Solas in a relationship - Sorrow is nothing. Heart is nothing. Or "There is no sorrow. There is no heart."
Translation One: The demon knows of Fen'harel and his true nature. That is clear. However, Fen'harel cannot have any pride when it would be wasted on the dead. Or, as he later put, the people.
Translation Two, and especially more far-fetched, so bear with me: The entire scene is a play-on-words. The English translation would be: Tell me, Trickster. My victorious comrade of Nothing. Your pride emerges from your dead. Or in other words: Speak to me, Trickster. The victor of the Blight, whose pride emerges from the dead. While Banal can be used to literally say "nothing", banal has been used as an idiom in conjunction with the suffix -han for the Blight. Specifically, Banalhan: the place of nothing. The origins of the Blight. We know Solas must help his people. For what context, we do not know. But in the presence of the Darkspawn taint, the red lyrium's awakening, and the voices inside the red lyrium whose dreams have now returned, perhaps the demon and Corypheus, a Blighted Magister, would know best how far the taint goes. "Nothing is inevitable?" Or could it mean "The Blight is an inevitability?"
Alas, all is still a mystery to be unveiled.