Swahili is a relatively simple language.  It is phonetic.  It does not have irregular verbs.  However, nouns are distributed throughout six genders.  (The word “gender” simply means a certain grammatical class of a noun.  In grammar it can but does not have to refer to sex.  It can refer to dangerous things or flat things or animals or any other kinds of thing.)  Swahili is not the champion language in regard to the number of genders.  The Kivunjo language of Tanzania which, like Swahili, belongs to the Bantu family of languages, has sixteen genders.

When people study Swahili or Kivunjo, every time they learn a noun, they have to memorize that noun’s gender.  Every time students of Swahili want to put a noun in the plural, they have to recall which of the six genders it belongs to, recall the method which that gender utilizes to form the plural, and apply that particular method and not one of the others.  In order to speak Swahili correctly and fluently this knowledge must come not after taking a few seconds to think about it but instantaneously, reflexively.

Someone speaking German has to do the same thing, but with three genders.  Someone speaking Spanish or French has to do the same thing, but with two genders. 

Even in the case of a language with two genders, learning the gender of each noun and applying it correctly is a very complex process.  In French (or Spanish or German or Latin or many other languages as well) every time you learn a new noun, you have to learn its gender.  When you want to use the word “the” or “a” in front of it, you have to choose the form of “the” or “a” that corresponds to the gender of that particular noun.  “A door”, which is feminine, is “une porte” but “a wall”, which is masculine, is “un mur.” “The door” is “la porte” but “the wall” is “le mur.”

You cannot depend on logic to tell if a French noun is masculine or feminine.  “A man” (un homme) is masculine and “a woman” (une femme) is feminine.  However, “a beard” (une barbe) is feminine and “breasts” (seins) is masculine.  You have to take a little bit of time to learn the gender of each of the thousand or thousands of nouns you have to know to speak the language.  This adds up to more hours of work.  And even you learn the gender of a great many nouns, if you do not have occasion to use certain nouns for a long period of time, you may find that you have forgotten what you once knew.

If you use an adjective to go along with the noun, you have to remember if that adjective has just (a) one form that goes with both masculine and feminine nouns or (b) a masculine form that goes along with masculine nouns and a feminine form that goes along with feminine nouns.  The French word for “green” has two forms, vert that goes along with masculine nouns and verte that goes along with feminine nouns, but the French word for “red” has just one form, rouge, which goes with both masculine and feminine nouns.

It is amusing to note that the French adjectives that mean “masculine” and “feminine” each have two forms, one that goes along with masculine nouns and one that goes along with feminine nouns.  However, the oddities involving gender in French get weirder than this.  There are a few French nouns which are masculine in the singular but feminine in the plural, and there is one, gens (people), which has only a plural form but which is sometimes masculine, and sometimes feminine, according to a special set of rules.

If an adjective follows gens, the adjective (and consequently, gens) is masculine, but if the adjective comes in front of gens, then the adjective (and, consequently, gens) is feminine unless that adjective happens to end with a silent e in its masculine form, in which case gens once again is masculine.

Gens is an extreme case but it illustrates the utter lack of logic when it comes to the gender classification of the overwhelming majority of French nouns and adjectives.

Compare this with English.  There are no genders to learn.  Every English noun takes the definite article “the” without exception.  It takes the indefinite article “a” (or “an” in front of a vowel sound).  Adjectives come in one form.  All you have to learn is the adjective.  You do not have to learn a different form for use with certain nouns and another form for use with other nouns.

Zamenhof used a very simple system in Esperanto.  He provided just one form for the definite article.  La and only la means “the.”  There is no indefinite article, no counterpart to the English words “a” and “an.”  (One function of these little words is to show that the following word is a noun.  Esperanto uses the o-ending that nouns take to do that job.)  Only a language like Russian is simpler when it comes to the article.  Russian gets along without articles, just as Chinese gets along without a mandatory plural form for nouns.

Esperanto adjectives do not change according to gender because, as in English, Esperanto nouns and adjectives do not come in different genders.

The learning burden when it comes to French genders amounts to hundreds of hours of extra work.  The problem of genders in French provides a great many opportunities for making mistakes, opportunities for error which simply do not exist in either English or Esperanto.