In modern Japanese, while the use of kanji facilitates reading due to compression of meaning within a writing space, it also obfuscates etymology in the language, as compared to languages with a written alphabet.
For example, take the Japanese word for eyeglasses, which is 眼鏡, read as めがね (megane). The kanji word came from Chinese, and the Japanese reads it using their native pronunciation, kunyomi. If we write it with respect to its etymology (and pronunciation), we can write with other kanji: 目金 , read in the same way. In the latter case, the etymology of the Japanese word for eyeglasses becomes clearer. The word is a compound of the words ‘eye’ and ‘metal’, referencing the metal frame of eyeglasses at the time of the word’s coinage.
Let us examine another example, the Japanese word for thunder/lighting 雷, read as かみなり (kaminari). Let us write it with respect to its etymology (and pronunciation): 神鳴り, read in the same way. The etymology of the word now jumps at us. The word means ‘the sound of god(s)’.
For our final example, let us look at the Japanese word mirror, which is 鏡, read as かがみ (kagami). Again, we can write the word with respect to its etymology. However, this time, we cannot write it with respect to pronunciation due to pronunciation changes over time because the Japanese word for shadow 影, which we read today as かげ (kage), used to be pronounced as かが (kaga) at the time of coinage of the Japanese word for mirror. The word compound that we have is 影見, which is read as かがみ (kagami), and it means seeing a shadow, which is quite poetic.
I do not advocate writing Japanese with respect to etymology because we can write more concisely following the modern conventions of the language. For example, we can write the Japanese word for thunder/lightening using one kanji instead of 4 kana. Writing Japanese with respect to etymology is, however, an interesting exercise to see how the etymology of words jumps out at us.
