* Limitations of earlier scripts: Before the Greek alphabet, Greeks, like other peoples in the Near East, primarily used syllabic scripts like Linear B. These scripts represented syllables, not individual sounds (phonemes), making them cumbersome and less flexible for representing the nuances of spoken language.
* Adoption and adaptation of Phoenician script: Around the 8th century BC, the Greeks adopted the Phoenician alphabet, a consonantal script. This was a crucial step because it represented individual sounds (consonants). The Phoenicians' alphabet was already an improvement over syllabaries, being simpler and more efficient.
* Innovation of vowel sounds: The Greeks made a significant innovation: they adapted some of the Phoenician consonant symbols to represent vowel sounds. This was a revolutionary development, as it allowed for a much more accurate representation of the spoken language, enabling more precise and nuanced writing. This feature is what truly distinguishes the Greek alphabet from its Phoenician predecessor and significantly enhanced its ability to represent language.
In short, the Greek alphabet exists because of a combination of practical necessity – the need for a more efficient and accurate writing system – and an ingenious adaptation and refinement of a pre-existing consonantal script which allowed for the representation of vowel sounds, leading to a much more complete and powerful system of writing. This innovation was a landmark achievement in the history of writing systems and greatly influenced the development of alphabets worldwide.