Here's why:
* The "a" in "laid" is unstressed. This means it's not pronounced with the same emphasis as a stressed vowel.
* Unstressed vowels often reduce to the schwa sound. The schwa sound is a neutral vowel sound, represented by the upside-down "e" symbol (ə).
Therefore, the "a" in "laid" is pronounced with the schwa sound, making it sound like "lay-əd".