One of his notable writings is the "Institutiones linguae Germanicae" (Rules of the German grammar) written in Latin for Hungarians, of which special edition was published in Halle in 1730 for Hungarian students studying in Germany. He also wrote a popular book, ""Der ungarische Sprachmeister" (Hungarian language master)", on Hungarian grammar for Germans. He mistakenly suspected that the Hungarian language was relative of the Hebrew one. In the one work of him whose name is ""Literatura Hunno-Scythica"" published in 1718, Bél endeavoured to prove that there existed, at one time, a Hun-Scythian alphabet, of which he thought that that must have been known to the Székelys.