This article concerns content exclusive to Warcraft RPG and thus unlikely to be canon.
Ignan is the language spoken by fire elementals from the Firelands. It is also known by conglomerates with the sub-type of fire. Ignan is, perhaps, a dialect of Kalimag.
The Half-Elven Banshee called Ielephia (a female Rogue) also knew the language.
The term Ignan shows up in the Kalimag phrase, "Ignan'kitch" in the Kalimag language parser.
This article or section includes speculation, observations or opinions possibly supported by lore or by Blizzard officials.*
"Ignan" has an apparent connection to DnD derived generic languages, which apparently can be found in DnD rule books.