The only vowels that can be employed in this connection are _o_ and _a_, which, as a matter of fact, occur very frequently as the terminations of substantives and adjectives in the Slavonic languages, as well as in I. and S. Since grammatical gender, as distinct from sex, cannot be permitted in an artificial language, it is not possible to employ _o_ and _a_ as in natural languages, where the former is often, though not exclusively, used for the masculine (I. S., but in R. and Polish for the neuter), and the latter similarly for the feminine. One might be inclined to employ _o_ for the male and _a_ for the female sex, with the result that one would have no termination for inanimate things, abstract ideas, or living beings whose sex is not a matter of importance at the moment. The carrying out of this rule, however, leads to considerable difficulties which would take too long to enter into here. (This is one of the points which led to most discussion in the Delegation Committee.) As a matter of fact, a very great deal can be said in favour of the Esperanto usage of _o_ for the substantive and _a_ for the adjective, and, as Couturat has remarked, _la bona viro_ is not any stranger than the Italian _il buono poeta_. We need have no compunction in leaving the qualifying adjective without inflection, as is done, for instance, in English. The ending _-i_ is very suitable for the plural of substantives, being used for this purpose in Italian, in Russian and the other Slavonic languages, as well as in modern Greek; it is also tolerably familiar to the English in foreign words, such as _banditti_. The only termination which might dispute the honours with _-i_ is _-s_ (F., although usually silent, S., E., G. partly, and Dutch), but _-s_ cannot be used if we employ the accusative termination _-n_, as neither _virosn_ nor _virons_ could be permitted.