When a child has an ear infection, they don't need anything fun or engaging. They need ciprofloxacin, which is arguably very boring (it's just a white pill they swallow with water), but it works. When most people are trying to learn a second language, their brain actively resists language acquisition, and what they need is a "language learning pill": psycholinguistic technology that will override that resistance and help the brain acquire a new language.
And I am not talking about "a new magic pill." For decades we've known exactly how to teach components of the language system in the most efficient way. Best way of learning vocabulary? Adaptive spaced repetition. Best way of learning a foreign sound system? High-variability phonetic training. Best way of learning writing? Self-regulated strategy development.
What's been really frustrating is that it has been anything but easy (and sometimes plainly impossible) for teachers to use those best-available methods. And that's why, back in 2011, we started
the Linguatorium project: to develop tools that would implement the best-available methods of language learning in a way that's easy for teachers and non-taxing on students. Tools that are almost as easy to use as ciprofloxacin, yet are as highly effective. When using an app for 10 minutes a day for a semester leads to a three-fold increase in long-term vocabulary retention (as shown in
this double-blind, placebo-controlled, peer-reviewed study), I call that "effective."