The aim is to add Standard English to the repertoire, not to replace other dialects or languages.
It was to serve as an international auxiliary language, that is, as a universal second language, not to replace ethnic languages.
Though Esperanto has not replaced existing languages, it should be remembered that such was not the intent of its originator.
For example, the Latin that came to replace local languages in present-day France during Roman times was influenced by Gaulish and Germanic.
During those millennia, other Austronesian speakers entered the Philippines in large enough numbers to leave a linguistic mark but not to replace established languages.
Russian language as well replaced Yiddish and other languages as the main language of many Jewish communities inside the Soviet Union.
Lithuanian nobility self-polonised, replacing Lithuanian and Ruthenian languages with Polish although the process took centuries.
By 1945 the Japanese language replaced Micronesian languages in day-to-day communications.
The goal was giving an international communication language, that is, as a universal (world) second language, not to replace national languages.
They gradually replaced their Dutch and Frisian languages with the Plautdietsch dialect spoken in the area, blending into it elements of their native tongues.