Grammatical gender as in F or D, where the word for `chair' is feminine in one and masculine in the other language (la chaise, der stuhl), can of course have no place in an international language. But all constructed languages do have, and must have, expressions for the natural sex-differences, in a few cases in separate words (as when words for father and mother have different roots), but generally by means of grammatical endings, and in some of these languages this latter expedient is even extended to the expressions for father and mother, man and woman, e.g. Esp patro father, patrino mother. Further, these languages have different forms for some pronouns at any rate according as they are used of one and the other sex, corresponding to E he, she, in spite of the fact that many languages do not recognize the necessity of this distinction, thus Finn. hän means he and she indifferently.
It was an important step in advance, when Ido after having had for some years the Esp system established common-sex substantives, e.g. spozo husband or wife, patro parent, with derivative endings for both sexes: spozulo husband, spozino wife, patrulo father, patrino mother (though it yielded to sentimental reasons, which some look upon as prejudices, by also allowing the use of matro for `mother'). Ido also created a common-sex pronoun for the third person, lu by the side of masc. il (ilu) and feminine el (elu). This has been felt by all Idists as a great advantage, as it does away with the clumsy use of "he or she" as well as with what many feel to be illogical, the use of the plural they in combinations like E "Nobody prevents you, do they?" or "Everybody took their hats," or "No one means what they say when they pay compliments," etc.
But while the principle is sound, the way in which it is carried out in Ido does not deserve praise in every respect. It would have been better if it had been possible to denote the same modifications by means of the same process in pronouns and substantives. The feminine ending -in-, inherited from Esp, is one of the rare cases in which the derivative endings of that language are not framed a priori, but are taken from actual languages: -in is known from D königin queen, Dan lærerinde female teacher, E tsarina, landgravine, etc., and the only objection that may be made refers to the application of the substantive ending -o to it, as this is felt to be a masculine ending rather than one common to both sexes. But -ulo is entirely a priori, and the sound of it is not particularly pleasant.
It should be noted, also, that some words had to be changed, because the -in- found in national languages might be mistaken for the feminine suffix, thus Esp has rabeno instead of rabino, and Ido mandareno instead of mandarino (though -in- has been admitted in mandarino `mandarin orange'). As Ido has diciplino for `discipline,' it could not at the same time have diciplo for 'disciple,' and therefore took dicipulo for `disciple' or `pupil' of either sex, which makes dicipulino for a female and dicipululo (!) for a male pupil. Even stranger than this is the treatment of the word for `cousin'; Esp has kuzo for a male and kuzino for a female cousin, consequently Ido has kuzo as a common-sex word, and kuzulo, kuzino for the two separate sexes. This is but one step less ridiculous than Zamenhof's treatment of another word: he adopts D fräulein `miss' in the form fraulino, and then subtracts the ending -ino to get a masculine fraulo, which is his word for a non-married man or bachelor, with total disregard of the fact that in D fräulein the sex is indicated by frau and that -lein is simply a diminutive ending as in männlein `little man.' The history of international languages is not totally devoid of humorous elements.
If we want to base our international grammar as far as possible on what is known from national languages, the best endings are those which Idiom Neutral, Occ, and some other languages have taken from I P S, -o for masculine and -a for the feminine (cf. such names as Antonio, Antonia), which then of course are extended to cases in which the Romanic languages have -e, e.g. patro for I S padre; if then we take -e for indefinite sex, we see the advantage of liberating ourselves from the Esp strait-jacket of having -o in all substantives (even primadonna being made into primadono), and we get the following natural sets of words:
artiste artist, artisto male a., artista female a. instruktiste teacher, instruktisto male t., instruktista female t. filie child (in relation to parents), filio son, filia daughter. infante child, baby, infanto, infanta. kusine cousin (either sex), kusino, kusina. fratre brother or sister, fratro, fratra. home human being, homo man, homa woman. kavale horse, kavalo stallion, kavala mare. kate cat, kato, kata, etc.
Note especially the plural forms in -es: me have six fratres, du fratros e quar fratras; men patres es in London, my parents are in London.
Onkles uncles and aunts, onklos uncles, onklas aunts. Here Italian, which has zio uncle, zia aunt, says zii for uncles and aunts.
By the side of some of these forms it may be practical to have separate words, thus matra by the side of and synonymous with patra; viro and fema by the side of homo and homa for (grown-up) man and woman.
Esp and Ido have the prefix ge- for both sexes combined: gepatri parents, gesiori ladies and gentlemen. This is totally superfluous and is contrary to most people's speech instinct, the more so as Zamenhof took this prefix from the solitary word D geschwister `brothers and sisters,' where it no more has relation to sex than the same (collective) prefix has in gepäck luggage, gewitter storm, gespräch conversation, etc.
When at the meetings of the Delegation Committee in Paris, 1907, I proposed -a as a feminine ending as in Idiom Neutral instead of Esp -ino, I was met with the objection that it would be difficult to form new derivatives from these words in -a (homaala by the side of homoala and homala would not do), and as I had no answer ready to that objection, I agreed with a shrug of the shoulder to the adoption of -ino. But in my present scheme I have a way out, for it is possible to insert the genitive-mark -n before -al, etc., fratronal brotherly, fratranal sisterly (fratral brother-or-sisterly); homonaro a crowd of men, homanaro of women.
Now, no previous constructor of international languages seems to have thought of applying the same system to pronouns, thus le he or she, lo he, la she; les they mf., los F eux, ils, las F elles.
(Occ here has nom. il, illa, acc. le, la, pl. nom. il(l)i, acc. les, thus irregular formations in which neither the number nor the sex nor the case is always indicated by the same means.)
Further: nule no one, nulo no man, nula no woman. omne everybody, omno every man, omna every woman. irge anybody, irgo any man, irga any woman. altre some one else, altra some other woman. kelke somebody, kelko, -a. te that man or woman, to that man, ta that woman (te kel he or she who). dise this man or woman, diso, disa.
Thus of course also with "substantivized adjectives" (adjectives as primaries), e.g. olde old man or woman, oldo old man, olda old woman, oldes old people.
A few examples of the common-sex forms: si omne veni kand le deve, nule besona varta if everybody comes when he should, no one has to wait. La nultem refusa helpo a povre si le fa omnum por helpa se self she never refuses help to a poor man (man or woman) if he or she does everything to help himself or herself. Que ha deklara ke le non besona labora? Who has declared that he (or she) need not work?
There are some pronouns which do not require any sex distinction, thus me `I' (one can easily see which is the sex of the speaker, without having expressly to say it); thus also the pronoun for the second person vu, and similarly the reflexive se: lo admira se, etc. With the interrogative pronoun, the distinction may be made: quo what man, qua what woman; but generally the common-sex form que will be used: que dikted tum? `Who said that?' - as the speaker could not know beforehand whether it was a man or a woman. The old Romans sometimes asked: Quis quæve dixit illud?