Here's why:
* Origin: Esperanto is a constructed language created by L.L. Zamenhof in the late 19th century. Spanish, on the other hand, is a Romance language that evolved from Latin.
* Grammar: Esperanto has a simplified grammar with a regular system of word endings and few exceptions. Spanish, like other Romance languages, has a more complex grammar with irregular verbs, gendered nouns, and multiple verb tenses.
* Vocabulary: Esperanto borrows words from many languages, often with simplified forms. Spanish, like other Romance languages, has a vocabulary primarily derived from Latin.
* Speakers: Spanish is spoken by hundreds of millions of people worldwide, primarily in Latin America and Spain. Esperanto has a much smaller number of speakers, mainly in Europe and Asia.
While Esperanto and Spanish share some similarities in vocabulary, particularly in scientific and technical fields, they are distinct languages with different origins, grammars, and uses.