PaulS:
There's a lot of research on how we learn. Most of it seems to agree that we don't actually retain anything until we've slept. So, this is excellent advice. Take a break; take a nap. You'll retain a lot more.
James Burke did an excellent and entertaining series in 1980 titled The Real Thing that goes into neuro to explain about wetware. Through 5 programs he builds a picture of how things work (to then knowledge, including a scanning micrograph of a neuron growing a connection) but shouldn't and then is the 6th one that introduces language. A poor copy is up on youtube but the content isn't lost.