Why most of auxiliary languages cannot be implemented

In the 19th century, the creation of Esperanto by Mr Zamenhof began a massive movement of constructed international auxiliary languages, which influenced many others such as Ido, Interlingua, etc. These languages are dedicated to achieving borderless international communication for all humanity. Although they did not officially succeed, could they still become an official international language in the future, and why they probably could not? The following paragraphs will explore this question by mainly examining Esperanto.

Firstly, although the grammar of auxiliary languages is regular unlike English and other natural languages, most of their design cannot be considered as international but European. For example, in the phonetic system of Esperanto, although all phonemes are completely linked with the orthography, there are many sounds which could be very confusing and hard for non-European speakers to pronounce, e.g. [r], [ʃ ], [h] and [x], [ʒ], [d͡ʒ], etc. Many of these sounds are uncommon in many global languages and some of them are even not in all European languages such as [r] which does not exist in English, French, and German.

Secondly, although the grammar is mostly simplified, learning them is still as costly as learning natural languages. One still has to learn a new and large lexicon and many grammatical concepts which are not in many languages. Sometimes they are even harder due to a lack of learning resources and media content.

In conclusion, the design of most constructed auxiliary languages is not good enough for international use. Although they have rigorous grammars, they are still not universal enough to replace English, which became the Lingua Franca through economic and political success, and has already established such fundamentals of technology and resources on a global scale.