To someone who spent years learning Chinese as a second language, and then made my living for years as a Chinese-English interpreter, that was pretty impressive.

The economics of the issue is that a machine interpreter just has to be as good as a human interpreter at the same cost. That's a reachable target with today's computer technology. EVERY time I've heard someone else interpreting English or Chinese into the other language, I have heard mistakes, and I am chagrined to remember mistakes that I made over the years. We can't count on error-free machine interpretation between any pair of languages (human language is too ambiguous in many daily life cases for that), but if companies develop tested, validated software solutions for consecutive interpreting (what I usually did, and what is shown in the video) or simultaneous interpreting (the harder kind of interpreting in demand at the United Nations, where even in the best case it is not always done well), then those companies will be able to displace a lot of human professionals who rely on their language ability to make a living.

Right now a lot of interpreters in the United States make a lot of part-time income from gigs that involve suddenly getting telephone calls and joining in to interpret a telephone conversation in two languages. This is often necessary, for example, for physician interviews of patients in emergency rooms or pharmacist consultations with patients buying prescribed drugs (where I last saw a posted notice on how to access such an interpretation service). The IBM Watson project is already targeted at becoming an expert system for medical diagnosis, and patient care markets will surely provide a lot of income for further development of software interpretation between human languages.

It's still good for human beings to spend the time and effort to learn another human language (as so many HN participants have by learning English as a second language). That's a broadening experience and an intellectual delight. But just as riding horses is more a form of recreation these days than a basis for being employed, so too speaking another language will be a declining factor in seeking employment in the next decade.