L.L. Zamenhof's international auxiliary language — fully regular grammar (no exceptions), 16 rules, vocabulary roots from Romance/Germanic/Slavic, full grammar (plurals, participles, accusative, conditional, correlatives), every life-domain vocabulary set, idioms & proverbs, country-by-country Esperanto communities, Pasporta Servo, the Universal Congress, Esperanto online (Lernu, Vikipedio, Duolingo), comparison with Volapük / Ido / Interlingua / Lojban / Toki Pona, history of suppression and survival, native-speaker families, AI-era machine translation, and certification paths. 2115 lessons across 141 units.