The main difficulty in the reading of Babylonian and Assyrian proper names arises from the preference given to the "ideographic" method of writing them. According to the developed cuneiform system of writing, words may be written by means of a sign (or combination of signs) expressive of the entire word, or they may be spelled out phonetically in syllables. So, for example, the word for "name" may be written by a sign MU, or it may be written cut by two signs shu-mu, the one sign MU representing the "Sumerian" word for "name," which, however, in the case of a Babylonian or Assyrian text must be read as shumu - the Semitic equivalent of the Sumerian MU. Similarly the word for "clothing" may be written SIG-BA, which represents again the "Sumerian" word, whereas, the Babylonian-Assyrian equivalent being lubushtu it is so to be read in Semitic texts, and may therefore be also phonetically written lu-bu-ush-tu. This double method of writing words arises from the circumstance that the cuneiform syllabary is of non-Semitic origin, the system being derived from the non-Semitic settlers of the Euphrates valley, commonly termed Sumerians (or Sumero-Akkadians), to whom, as the earlier settlers, the origin of the cuneiform script is due.

This script, together with the general Sumerian culture, was taken over by the Babylonians upon their settlement in the Euphrates valley and adapted to their language, which belonged to the Semitic group. In this transfer the Sumerian words - largely monosyllabic - were reproduced, but read as Semitic, and at the same time the advance step was taken of utilizing the Sumerian words as means of writing the Babylonian words phonetically. In this case the signs representing Sumerian words were treated merely as syllables, and, without reference to their meaning, utilized for spelling Babylonian words. The Babylonian syllabary which thus arose, and which, as the culture passed on to the north - known as Assyria - became the Babylonian Assyrian syllabary,[32] was enlarged and modified in the course of time, the Semitic equivalents for many of the signs being distorted or abbreviated to form the basis of new "phonetic" values that were thus of "Semitic" origin; but, on the whole, the "non-Semitic" character of the signs used as syllables in the phonetic method of writing Semitic words was preserved; and, furthermore, down to the latest days of the Babylonian and Assyrian empires the mixed method of writing continued, though there were periods when "purism" was the fashion, and there was a more marked tendency to spell out the words laboriously in preference to using signs with a phonetic complement as an aid in suggesting the reading desired in any given instance.

Yet, even in those days, the Babylonian syllabary continued to be a mixture of ideographic and phonetic writing. Besides the conventional use of certain signs as the indications of names of gods, countries, cities, vessels, birds, trees, etc., which, known as "determinants," are the Sumerian signs of the terms in question and were added as a guide for the reader, proper names more particularly continued to be written to a large extent in purely "ideographic" fashion. The conservatism which is a feature of proper names everywhere, in consequence of which the archaic traits of a language are frequently preserved in them, just as they are preserved in terms used in the ritual and in poetic diction, is sufficient to account for the interesting fact that the Semitic settlers of the Euphrates valley in handing down their names from one generation to another retained the custom of writing them in "Sumerian" fashion, or, as we might also put it, in "ideographic" form. Thus the name of the deity, which enters as an element in a large proportion of the proper names,[33] was almost invariably written with the sign or signs representing this deity, and it is only exceptionally that the name is spelled phonetically.

Thus the name of the chief god of the Babylonian pantheon, Marduk, is written by two signs to be pronounced AMAR-UD, which describe the god as the "young bullock of the day" - an allusion to the solar character of the god in question. The moon-god Sin is written by a sign which has the force of "thirty," and is a distinct reference to the monthly course of the planet; or the name is written by two signs to be pronounced EN-ZU, which describe the god as the "lord of wisdom." The god Nebo appears as PA - the sign of the stylus, which is associated with this deity as the originator and patron of writing and of knowledge in general, - or it is written with a sign AK, which describes the god as a "creator."

Until, therefore, through parallel passages or through explanatory lists prepared by the Babylonian and Assyrian scribes in large numbers as an aid for the study of the language,[34] the exact phonetic reading of these divine names was determined, scholars remained in doubt or had recourse to conjectural or provisional readings. Even at the present time there are many names of deities, as, e.g. Ninib, the phonetic reading of which is still unknown or uncertain. In most cases, however, these belong to the category of minor deities or represent old local gods assimilated to some more powerful god, who absorbed, as it were, the attributes and prerogatives of these minor ones. In many cases they will probably turn out to be descriptive epithets of gods already known rather than genuine proper names. A peculiar difficulty arises in the case of the god of storms, who, written IM, was generally known in Babylonia as Ramman, "the thunderer," whereas in Assyria he also had the designation Adad. In many cases, therefore, we may be in doubt how the sign IM is to be read, more particularly since this same god appears to have had other designations besides Ramman and Adad.

Besides the divine element, proper names as a rule in the Babylonian-Assyrian periods had a verbal form attached and a third element representing an object. Even when the sign indicative of the verb is clearly recognised there still remains to be determined the form of the verb intended. Thus in the case of the sign KUR, which is the equivalent of naṣāru, "protect," there is the possibility of reading it as the active participle nāṣir, or as an imperative uṣṣur, or even the third person perfect iṣṣur. Similarly in the case of the sign MU, which, besides signifying "name" as above pointed out, is also the Sumerian word for "give," and therefore may be read iddin, "he gave," from nadānu, or may be read nādin, "giver"; and when, as actually happens, a name occurs in which the first element is the name of a deity followed by MU-MU, a new element of doubt is introduced through the uncertainty whether the first MU is to be taken as a form of the verb nadānu and the second as the noun shumu, "name," or vice versa.