26 English letters, which are the letters on which English is based now, ***26. The modern English alphabet completely borrows 26 Latin letters. The so-called "Latin alphabet" is the alphabet of words used by ancient Romans. The same letters constitute the basic Latin letters of ISO.
The origin of 26 English letters:
The English alphabet borrowed from the Latin alphabet invented by the ancient Romans, which originated from the Greek alphabet, which evolved from the Phoenician alphabet and was deeply influenced by the ancient Egyptian holy sites. During the new kingdom of ancient Egypt, most Phoenicians were under Egyptian rule, and Phoenicians were deeply influenced by Egyptian culture.
In fact, before the Phoenician alphabet appeared, there were so-called primitive letters in Canaan or Sinai Peninsula, which were basically hieroglyphics of ancient Egypt. The Wikipedia page lists ten Egyptian symbols and the original Sinai alphabet, Phoenician alphabet, ancient Hebrew alphabet and Aramaic alphabet.