According to "Pedoman Umum Ejaan Bahasa Madura yang Disempurnakan" (2008, page 8), names of languages are supposed to be written with capital letters. Online book: http://repositori.kemdikbud.go.id/1761/1/Ejaan%20Bahasa%20Madura%20Yang%20Disempurnakan%20%282008%29.pdf