I fully agree that a lot of the difficulty with the tones is in pronouncing them at pace, and in internalizing how they interact with one another. However, thi

I fully agree that a lot of the difficulty with the tones is in pronouncing them at pace, and in internalizing how they interact with one another. However, this is still something that happens very early on when learning Chinese, and it takes nowhere near the same amount of invested time as learning thousands of vocabulary terms.