133 karma · joined March 19, 2013
You can learn the portion of IPA relevant to the language you're working on, as well has how each symbol translates to mouth movements.
Then you can use the IPA transcriptions available in some dictionaries to not only hear how the word sounds when pronounced by a native speaker, but also know what they are doing mechanically to produce those sounds.
This is especially helpful, because it can train you to identify and produce the different phonemes that your brain isn't attuned to for in your native language (one classic example is japanese speakers' difficulty with r and l, which happens because different languages make different decisions about what constitutes a unique sound).
There maybe a few gaps (particularly for supersonic flight) still being explored, but in general it's inaccurate to claim that we don't know how airplanes work.
First, the per-acre yields for heritage varietals are much lower than those cited in the article, and I suspect that some crops have improved quite a bit more than others.
Second, I would speculate that grains' biggest advantage in neolithic times was storage duration, not mass or volume. Today if we have a crop-killing drought we can transport crops from other regions. It's expensive and inconvenient but not often life threatening. Even as little as a couple hundred years ago, any society dependent on agriculture would need a crop that could be stored for multiple years to protect against drought.