“The twenty eight letters of the Esperanto alphabet are based on a simple principle: for each letter one sound, and for each sound one letter. The tonic accent always falls on the penultimate syllable. There is only one article, la, invariable for words of all genders–thus la homo, la libroj, la abelo. Proper names do not take an article. There is no indefinite article.
Concerning the lexicon, the young Zamenhof had already noted that in many European languages there was a logic of suffixes that produced both feminine and many derivative forms (Buch / Bücherei, pharmakon / pharmakeia, child / childish, rex / regina, host / hostess, gallo / gallina, hero / heroine, Tsar / Tsarina), while the formation of contraries was governed by prefixes (heureux / malheureux, happy / unhappy, legal / illegal, fermo / malfermo, rostom / malorostom–the Russian for “high” and “low.”)
In a letter of 24 September 1876, Zamenhof described himself as ransacking the dictionaries of the various European languages trying to identify terms with a common root–lingwe, lingua, langue, lengua, language; rosa, rose, roza, etc. This was already the seminal idea of an a posteriori language.
Wherever Zamenhof was unable to discover a common root, he coined his own terms, privileging Romance languages, followed by the Germanic and Slavic ones. As a result, any speaker of a European language who examined an Esperanto word list would discover:
(1). Many terms that were easily recognizable as being similar or identical to his or her own;
(2). Terms which, though deriving from a foreign language, were still easily recognizable;
(3). Terms which, though strange at first sight, once their meaning had been learned, turned out to be easily recognizable; and finally,
(4). A reasonably limited number of terms to be learned ex novo.
Here are some examples: abelo (ape), apud (next to), akto (act), alumeto (match), birdo (bird), cigaredo (cigarette), domo (home), fali (to fall), frosto (frost), fumo (smoke), hundo (dog), kato (cat), krajono (pencil), kvar (quarter).
Esperanto also includes a comparatively large number of compound words. They are not inspired by the a priori projects, where composition is the norm, since the terms work like a chemical formula; Zamenhof could find compound words in natural languages (think of man-eater, tire-bouchon, schiaccianoci, to say nothing of German).
Compound words, moreover, permitted the exploitation of a limited number of radicals to the maximum. The rule governing the formation of compounds was that the principal word appeared at the end: thus–as in English–a “writing-table” becomes skribotablo.
The agglutinative principle which governs the formation of compound words allows for the creation of easily recognizable neologisms (cf. Zinna 1993).
From the radical stem, the neutral form is given by the suffix -o. This is not, as might appear, for example, to Italian or Spanish speakers, the suffix for the masculine gender, but merely serves as a mark for singular.
The feminine gender is “marked” by inserting an -in- between the stem and the singular ending -o. Thus “father / mother” = patr-o / patr-in-o, “king / queen” = reg-o / reg-in-o, male / female = vir-o / vir-in-o.
Plurals are formed by adding -j to the singular: thus “fathers / mothers” = patr-o-j / patr-in-o-j.
In natural languages many terms belonging to the same conceptual fields are frequently expressed by radically different lexical items. For instance, in Italian, given the conceptual field of parenthood, one must learn the meaning of padre, madre, suocero, genitori (father, mother, father-in-law and parents) before acknowledging that these terms belong to the same notional family.
In Esperanto, knowing the meaning of the radical patr, it is immediately possible to guess the meaning of patro, patrino, bopatro and gepatroj.
Likewise, in English (as well as in other languages) there are different endings for terms which all express a job or an occupation, like actor, driver, dentist, president, surgeon.
In Esperanto the words for all occupations are marked by the suffix –isto, so that anyone who knows that dento is “tooth” will automatically know that a dentisto is a professional who deals with teeth.
The rule for the formation of adjectives is also simple and intuitively clear: adjectives are formed by adding the suffix -a to the root stem: “paternal” = patr-a; and they agree with nouns in number: “good parents” = bonaj patroj.
The six verbal forms are not conjugated, and are always marked by six suffixes. For instance, for the verb “to see” we have vid-i (infinitive), vid-as (present), vid-is (past), vid-os (future), vid-us (conditional) and vid-u! (imperative).
Zinna has observed (1993) that, while the a priori languages and “laconic” grammars tried, at all cost, to apply a principle of economy, Esperanto follows a principle of optimization. Following the principle of economy, Esperanto abolishes case endings, yet it makes an exception of the accusative–which is formed by adding an -n to the noun: “la patro amas la filon, la patro amas la filojn.”
The motivation for this exception was that in non-flexional languages the accusative is the only case which is not introduced by a preposition, therefore it had to be marked in some way. Besides, the languages that, like English, had lost the accusative for nouns retain it for pronouns (I / me). The accusative also permits one to invert the syntactic order of the sentence, and yet to identify both the subject and the object of the action.
The accusative serves to avoid other ambiguities produced by non-flexional languages. As in Latin, it serves to indicate motion towards, so that in Esperanto one can distinguish between “la birdo flugas en la gardeno” (in which the bird is flying about within the garden) from “la birdo flugas en la gardenon” (in which the bird is flying into the garden).
In Italian “l’uccello vola nel giardino” remains ambiguous. In English, “I can hear him better than you” is ambiguous, for it can mean either “I can hear him better than you can hear him” or “I can hear him better than I can hear you” (the same happens in French with “je l’écoute mieux que vous,” or in Italian with “lo sento meglio di te“).
The Esperanto accusative renders this distinction very simply: the first case is “mi auskultas lin pli bone ol vi,” while the second is “mi auskultas lin pli bone ol vin.”
Umberto Eco, The Search for the Perfect Language, translated by James Fentress, Blackwell. Oxford, 1995, pp. 327-30.