Short answers, pulled from the story.
The first letters were invented by illiterate turquoise miners in the Sinai Peninsula during the Middle Bronze Age. These workers created graffiti in Egyptian turquoise mines that evolved into the Proto-Sinaitic script around the 19th century BC.
The Proto-Sinaitic script appeared around the 19th century BC and was discovered at Wadi el-Hol valley in 1999 by Egyptologists John and Deborah Darnell. Evidence of adaptation from Egyptian hieroglyphs in this script dates to the 18th century BC.
The Phoenician alphabet, conventionally called Proto-Canaanite, is the parent script of all western alphabets and developed before the 10th century BC. The oldest text in this script is an inscription on the sarcophagus of King Ahiram.
Sejong the Great created the Hangul alphabet in 1443, and the creation was planned by the government of the day. This unique featural alphabet places individual letters in syllable clusters with equal dimensions.
Kazakhstan made a transition to the Latin alphabet in 2021 after changing from an Arabic script to a Cyrillic script due to the Soviet Union's influence. This change aligns the writing system with the contemporary spoken language.