The correct pronunciation is NOT “Nyla” or “Nila” but “Niela” and is written with two dots (diacritical mark: diaeresis not umlaut) above the letter I as: ï. Another example of the CORRECT pronunciation are the words “naïve” or the name of the Opera, “Aïda”. Since the name is not of American/English origin, when American/English-speaking people hear the name correctly pronounced, they misspell it as “niela” or “nyelah". When they SEE the name in print, they mispronounce it as “nail-ah” or “nyla” or “nila”.