<p>PaperChaserPop, maybe you are right.
I wrote that’s my “guess” because it is solely based on my personal feelings. But in my personal experience, learning foreign languages and musical instruments are similar that I had (have) to practice everyday. I needed to practice violin everyday for 16 years to reach to some level in my childhood. But I did some concentrated study time to time to get good points in other subjects like Math, Physics and so on. Missing only one day practice is worth another several days in case of learning languages, music instruments and some sports. But in Math, several days rest can result in better idea.</p>