The high score for Turkish may be similar to the reasons for Esperanto that you imply: the alphabet was designed and adopted in 1928 to specifically fit the pho

The high score for Turkish may be similar to the reasons for Esperanto that you imply: the alphabet was designed and adopted in 1928 to specifically fit the phonetics of the [Anatolian] Turkish language. Some hiccups, mostly with Arabic loan words remain (famous example: most native speakers mispronounce the word “katil” - murderer) but learning to read/write is ridiculously simple. My son, who was born in the US was never formally taught to read, he picked it up during brief stays in Turkey during summers.