Constructed language
A planned or constructed language is a language whose phonology, grammar, and vocabulary have been consciously devised instead of having developed "naturally".
Some such language are experiments or only intended to be used in fictional science fiction or fantasy settings.
Others are intended to be used as auxilliary languages in international communications.
Some constructed languages are argued to be superior to natural languages. They may be argued to be easily learned, completely regular without any irregular exceptions, easily pronounced, lacking language ambiguities, encourage logical and precise thinking, and so on. Such languages may also be argued to have the advantage of not favoring the natural language of a particular ethnicity and thus not giving this ethnicity an unjustified advantage.
Regardless, no constructed language has been particularly successful. Esperanto (constructed by the Jewish Ludwig Lazarus Zamenhof) is by far the most widely spoken constructed language, with up to 2 million people speaking it to some degree, but mostly only as a hobby. The choices made when constructing Esperanto have also been criticized for various reasons.
More generally, there are various criticisms against constructed languages in general but these criticisms may also apply to natural languages. Thus, for example, many dialects and small languages are gradually disappearing, but not due to competition from constructed languages, but due to competition from larger natural languages. Critics of globalization may be critical of international auxilliary languages but there are already natural languages functioning as such.
Even if arguing for that every language and dialect should be preserved, then in international communications the parties will still usually communicate using some particular language that both parties understand. In practice English function as the international auxilliary language for historical reasons despite sometimes being argued to be a particularly difficult language to learn.
