Elative Absolute

This article in The Economist tries to determine which of the world's spoken languages is the most difficult to learn. Here's a sample:

For sound complexity, one language stands out. !Xóõ, spoken by just a few thousand, mostly in Botswana, has a blistering array of unusual sounds. Its vowels include plain, pharyngealised, strident and breathy, and they carry four tones. It has five basic clicks and 17 accompanying ones. The leading expert on the !Xóõ, Tony Traill, developed a lump on his larynx from learning to make their sounds. Further research showed that adult !Xóõ-speakers had the same lump (children had not developed it yet).

Beyond sound comes the problem of grammar. On this score, some European languages are far harder than are, say, Latin or Greek. Latin’s six cases cower in comparison with Estonian’s 14, which include inessive, elative, adessive, abessive, and the system is riddled with irregularities and exceptions....