[Elu] is the name by which is known an ancient form of the Sinhala language from which the modern vernacular of Ceylon is immediately received, and to which the latter bears is of the same relation that the English of today bears to Anglo-Saxon...The name Elu is no other than Sinhala much succeeded, standing for an older form, Hĕla or Hĕlu, which occurs in some ancient works, and this again for a still older, Sĕla, which brings us back to the Pali Sîhala.
Being a Prakrit, Eḷu is closely related to other Prakrits such as Pali. Indeed, a very large proportion of Eḷu word-stems are identical in form to Pali. The connections were sufficiently well known that technical terms from Pali and Sanskrit were easily converted into Eḷu by a set of conventional phonological transformations. Because of the prevalence of these transformations, it is not always possible to tell whether a given Eḷu word is a part of the old Prakrit lexicon, or a transformed borrowing from Sanskrit.