Languages have different purposes, and different groups that use them. Some are restricted to be used by a small group, others are official languages for countries and even other languages have an international role. 

Through time, some languages are regarded as not good enough because they have to borrow words from other languages. In some point of history, Latin was regarded as not good enough to express the greek ideas, and about a millenium later, French and English were considered too immature to ever replace Latin as a language for the church and other places.

Some languages are disregarded because they sound too bad, see myth eleven for that one, and others are ignored because they work different structurally, see myth 10 for that. 

Every language can be used for everything, it just needs time to evolve. You couldn't discuss the workings of software in Old English, it just needed a bit of time and evolution to Modern English. Given enough time, any language can be used.