The first tool is a habit. The second tool is a resource. The third tool could be called a trick, a technique, or a secret.
Basically it involves some sort of doubling up, or of coupling.
For example, there’s using two languages in parallel, listening while reading, or using a familiar grammar to ‘grow’ a sense of another.
It encourages working at speed, pattern recognition, skimming, skipping over, omitting, and ‘imperfect’ learning. It stops you from analyzing the language too much.
It keeps your conscious mind off-balance, and allows the brain to do its job the way it’s meant to.