The Maori language has been in decline for the past few decades in New Zealand. In an attempt to help revive the language, New Zealand's Prime Minister will have her daughter learn the Maori.
Amazon wants to increase their number of users in India because of their giant population. However, most of the population doesn't speak English so Amazon's going to break the language barrier.
This article has some pictures of Tolkien's notebooks that he created four elvish in. The languages he made for Lord of The Rings were fairly complex. They were all derived from each other and he even created historical evolution throughout the languages.
This article talks about the process that was used to create the alien Kilgnon language from Star Trek. It also talks about how its popularity spread and about how many people "speak" it.