Note: Do not rely on this information. It is very old.
N
N, the fourteenth letter of the alphabet, corresponding to the Phoenician nun ("fish"), was derived from the hieroglyphic sign for water. It is the nasal dental, holding the same relation to d and t, that m does to b and p. Hence d was often generated after n, as in thunder (Anglo-Saxon thunor). The "parasitic" letter which thus arose through careless pronunciation belonged to the palatal class if a palatal letter followed, to the guttural if it came before a guttural (e.g. sing-ging for sin-ging). In some words the n itself is parasitic, e.g. messenger for messager. M and n interchange before labials and dentals, e.g. comfort from Latin confortare; count from Latin comitem.