I've seen the names of many fruit varieties develop a number of alternative spellings, most likely the result of someone either perceiving a misspelling or simply trying to make a name easier for the public to pronounce. Karmijn de Sonnaville is one of these apples. I believe Karmijn is the Dutch word for 'Carmine' and is pronounced the same way: 2 syllables, silent J. Maybe over time it'll eventually become known as Carmine de Sonnaville. :)