150 ani d'Zamenhof qv'est inventoro d'lingu artus Esperantu

Wikipedia. Ludovic Lazarus Zamenhof (pronounced /ˈzɑːmɨnhɒf/ in English; born Eliezer Levi Samenhof, December 15, 1859 – April 14, 1917) was an ophthalmologist, philologist, and the inventor of Esperanto, a constructed language designed for international communication.

Cultural background
Zamenhof was born on December 15, 1859 in the town of Białystok in Poland (then part of the Russian Empire). He considered his native language to be his father's Russian (or perhaps Belarusian, which was not considered distinct from Russian at the time and which appears to have had a strong influence on Esperanto phonology), but also spoke his mother's Yiddish natively; as he grew older, he spoke more Polish, and that became the native language of his children. His father was a teacher of German, and he also spoke that language fluently, though not as comfortably as Yiddish. Later he learned French, Latin, Greek, Hebrew, and English, and had an interest in Italian, Spanish and Lithuanian.

In addition to the Yiddish-speaking Jewish majority, the population of Białystok was made up of three other ethnic groups: Poles, Germans, and Belarusians. Zamenhof was saddened and frustrated by the many quarrels between these groups. He supposed that the main reason for the hate and prejudice lay in mutual misunderstanding, caused by the lack of one common language that would play the role of a neutral communication tool between people of different ethnic and linguistic backgrounds.

Work for an international language
As a student at secondary school in Warsaw, Zamenhof made attempts to create some kind of international language with a grammar that was very rich, but also very complex. When he later studied English, he decided that the international language must have a simpler grammar. Apart from his parents' native languages Russian and Yiddish and his adopted language Polish, his lingustics attempts were also aided by his mastering of German, a good passive understanding of Latin, Hebrew and French, and a basic knowledge of Greek, English and Italian.

By 1878, his project Lingwe uniwersala was almost finished. However, Zamenhof was too young then to publish his work. Soon after graduation from school he began to study medicine, first in Moscow, and later in Warsaw. In 1885, Zamenhof graduated from a university and began his practice as a doctor in Veisiejai and since 1886 as an ophthalmologist in Płock and Vienna. While healing people there he continued to work on his project of the international language.

For two years he tried to raise funds to publish a booklet describing the language until he received the financial help from his future wife's father. In 1887, the book titled as "Lingvo internacia. Antaŭparolo kaj plena lernolibro" (International Language. Foreword And Complete Textbook) was published under the pseudonym "Doktoro Esperanto," or "Doctor Hopeful," from which the name of the language derives. For Zamenhof this language, far from being merely a communication tool, was a way of promoting the peaceful coexistence of different people and cultures.