Here's a breakdown of some factors:
* The origins of the alphabet: The English alphabet is ultimately derived from the Phoenician alphabet, which in turn influenced the Greek alphabet. The Phoenician alphabet didn't have vowels, but the Greeks adapted their system to include vowels, with "alpha" becoming the first letter.
* Order and Sound: The order of letters in the early Greek alphabet wasn't entirely based on sound, but it's likely that "alpha" was chosen as the first because it was a simple, common sound.
* Roman influence: The Romans adopted the Greek alphabet, and their order of letters became the basis for our modern English alphabet.
Important Note: The placement of letters in an alphabet isn't necessarily tied to their frequency or importance in a language. It's simply a matter of historical development and the way that writing systems evolved over time.