There is one more difficult letter in the alphabet, with which we shall here finally deal, namely z. In phonetic script this is now used everywhere for the voiced sound corresponding to the voiceless [s], and that is the value generally given to the letter in F E, e.g. E zinc, hazy, hazard, though the same sound is much more often written s, as in rose, visit(e). In slavic languages, too, z is used for the same voiced sound. But everywhere else the letter z is used differently, thus D for [ts], I for [ts] in some words, for [dz] in others, S for [phonetic symbol] as E voiceless th, Sc (where it is now used very sparingly) for [s]. There is therefore every inducement to throw out the question: could we not do without this ambiguous letter in Novial? In Esp and especially in Ido z is used extremely often, not only where F E write s between two vowels (rozo, amuzar, akuzar, fiziko), but also where the voiced sound is found only in one of these languages (krizo E crisis, bazo base, words beginning with iso- or ending with -ozo, E -ous), and even where neither language has the voiced sound (karezar caress, mazo mace, F massue, kazo case, F cas with mute s, komizo F commis, E salesman). It is no exaggeration to say that this excessive use of the letter z is one of the features of Ido which are least liked in many countries, except perhaps by the few professional phoneticians. To the many millions speaking D I S it will always be a stumbling-block. Dr. Talmey even goes as far as to propose for adoption a spelling like zaco for `sentence' in the grammatical sense. This is D satz disfigured by writing z for the North-German initial sound and by the Polish-Zamenhofian c before the substantive ending -o, the whole thus a very strong argument for a revision of the entire Esp-Ido system.
As we have seen, Ido is inconsistent; it is so even through writing s where according to its own principles it should undoubtedly have had z: frizo F frise E frieze, fusilo F fusil, gasoza F gazeux E gaseous (generally pronounced with z). The result of this somewhat chaotic distribution of s and z is that in writing Ido one is constantly obliged to look up words in a dictionary, and in speaking it one cannot help hesitating now and then, for no one can remember each word separately. I see no other way out of this difficulty than by doing what we did with c, ie. discarding z and substituting s everywhere.
I suppose no one can doubt that this consistent use of only one letter where Esperanto and Ido have three, c,s, and z, constitutes a very considerable simplification and lessening of the burden on memory. But there may be many interlinguists who will think that this is only possible at the cost of clearness, because as a matter of fact these sounds are often used in Esp and Ido to distiguish words that would otherwise be identical. I may put such anxious minds at ease by stating that it is possible without any great efforts to avoid all serious misunderstandings and ambiguities, and that this result is principally due to the doing away with of the Esp principle of having only one ending for each part of speech; as soon as we admit substantives with other endings than -o, distinctive forms present themselves quite naturally for several words, such as kasu case, Lcasus F cas, kase case, box, F caisse, D kasse; tase cup D F tasse, tasa be silent about, I tacere, with sb. taso; sinke zinc, sinko the act of sinking (vb sinka). The alphabetical list on p. 174 will show how it is possible to get out of all serious difficulties without disfigurements of well-known words, for it can hardly be called a serious defect in Novial that musa means a female mouse as well as a muse! (Ido musino and muzo with unnatural -o.)
I wonder how many Idists would be able to tell offhand which is which of pairs like lanco lanso, senco senso, traco traso, punco punso, baso bazo, deserto dezerto, friso frizo, laso lazo, maso mazo, paso pazo, traco traso. Even the best linguist has nothing to aid his memory in most of these words: everything is purely arbitrary, and some of the z's are found in words which in all national languages have the voiceless sound.
It is a natural consequence of the abolition of z, that Spaniards, Scandinavians need not trouble to learn the new sound z, and that we need no longer insist on the letter s being everywhere pronounced as the voiceless [s]: one is free to pronounce it as the voiced [z], as the French and English and a great many Germans and Italians will naturally feel inclined to do when it occurs between two vowels, as in rose etc. Englishmen may even say the verb usa, exkusa with [z] and the substantives uso, exkuso with [s] in accordance with the speech-habits of their native language. A modern phonetician will express this by saying that the two sounds [s] and [z] are not two phonemes in our international language, exactly as we saw above that the two sounds close and open e, which in F are phonemes (é and è), i.e. may serve to distinguish words, may be used indiscriminately in the I.L. This liberty to use either of two sounds for the same letter is of course a great advantage, and is totally different from the compulsory assignation of different phonetic values for one and the same letter according to its position, as is done in numerous national languages and in Occ with c and g.
The abolition of c and z in our international vocabulary does not, of course, mean that we want to use s instead of these letters everywhere: proper names must keep their spelling unchanged as long as their possessers do not alter them, and we shall therefore go on writing Cincinnati, Cività Vecchia, Scilly, Zwickau, Zulu, Szczebrzezyn, Cecil, Poincaré, Ibañez, etc. In the same way, chemists will probably go on using their interantional abbreviations for elements, Cu for copper, Cl for chlorine, Zn for zinc, etc., whatever we may do for our purposes with the corresponding vulgar words.