But how XD ? I mean the noun ends with ה and the plural has feminin form too. Plus in aramaic and arabic they have the same word "layla" and in both languages layla is feminin.
I can't have an accurate or even easy access to aramaic, but as well as i know, in arabic: the word ליל ليل is singular masculin, its plural is ليالٍ ליאלי. And לילה ليلة is singular feminin, and its plural is ليلات לילאת.