Who invented the alphabet?

The history of the alphabet started in ancient Egypt. By 2700 BCE Egyptian writing had a set of some 24 hieroglyphs which are called uniliterals, to represent syllables that begin with a single consonant of their language, plus a vowel (or no vowel) to be supplied by the native speaker. These glyphs were used as pronunciation guides for logograms, to write grammatical inflections, and, later, to transcribe loan words and foreign names. But the Egyptians never used these "letters" by themselves; they were always mixed in with pictograms, symbols representing whole words.

The first phonetic alphabet was invented by the Phoenicians, sometime before 1050 BCE.

The letters in the English alphabet are a mix of ancient rune characters and various Greek and Latin characters. It took over 1500 years to arrive at our modern English alphabet.

Early Christian leaders in Old English times tried to forbid using runes because they were of pagan origin, but the characters fit the language, so they were used anyway. Greek and Latin contributed more letters than any other source.