He tried to use similar economy in his dictionary as in the grammar, thinking that it did not matter what form a word took if it had a given meaning; so he began to invent words, taking care only that they should be as short as possible. For instance, he argued that the word "conversation" has 12 letters; why should not the same idea be conveyed by two, say, "pa"? He tried this by simply writing the shortest and most easily pronounced mathematical series of joined letters, and these he gave a defined meaning, e.g., ab, ac, ad, ... ba, ca, da, ... eb, ec, ed, ... etc. He, however, soon abandoned this idea, as he found these invented words very difficult to learn, and hard to remember, and thus he came to the conclusion that the word material for the dictionary must be Romance-Teutonic, changed only as regularity and other important conditions of the language required. He soon remarked that the present spoken languages possessed an immense store of ready-made international words known by all nations, and he commenced at once to make use of this unlimited supply.
One day, when he was in the 6th or 7th Class at the Gymnasium he, by chance, observed that the signs over shops had certain terminations, as we might notice in England, for instance, "Surgery," "Bakery," etc., and it then struck him for the first time that these terminations had certain meanings, and that by using a number of suffixes, each always having the same meaning, he might make out of one word many others that need not be separately learnt. This thought shed a ray of light upon his great and terrible vocabularies, and he cried out "The problem is solved!" He at once understood how important it was to make use of this power, which, in the national languages, plays only a blind, irregular and incomplete rôle. So he began to compare words, and to search out the constant and defined relationship between them. He cast out of his vocabularies a vast series of words, substituting for each huge mass a single suffix, which had always a certain fixed relationship to a root-word. He next remarked that certain words, which he had hitherto regarded as purely roots, might easily become formed words and disappear from the dictionary, such as patr-ino (mother), mal-larĝa (narrow), tranĉ-ilo (knife). Soon after this the Doctor had in manuscript the whole grammar and a small vocabulary.
In 1878, when he was in the 8th Class at the Gymnasium, the language was more or less ready, and his fellow students commenced to study it. On December 17th, 1878, they celebrated the birth of the language by a banquet, at which a hymn was sung, the commencing words being as follows:—
Malamikete de las nacjes
Kadó, kadó, jam temp’ está!
La tot’ homoze in familje
Konunigare so debá.
The language then was very different from what it is now, as the following translation will show:—
Malamikeco de la nacioj
Falu, falu, jam tempo estas!
La tuta homaro en familion
Unuiĝi devas.
"Let the enmity of nations fall, fall, for the hour is come. All mankind must be united in one family."
On the table, in addition to the grammar and dictionary, were some translations in the new language.
The Doctor’s fellow students were at first enthusiastic, but meeting with ridicule when they tried to discuss the language with their elders, they soon renounced it, and the Doctor hid his work from all eyes.
After he left school and was at the University, for five years and a half he never spoke of it to anyone. This secrecy tormented him. Compelled to conceal his thoughts and plans, he went scarcely anywhere, took part in nothing, and the best period of his life, his student years, were, for him, his saddest. Occasionally, he sought society, but it failed to enliven him, and he then tried to tranquillize his mind by writing poems in the language he was elaborating.