Here's why:
* The schwa sound (ə) is a very short, unstressed vowel sound. It's the most common vowel sound in English.
* In "open," the vowel sound is /oʊ/, which is a long vowel sound. It's the same vowel sound as in words like "go" and "low."
Let me know if you'd like to hear some examples of words with the schwa sound!