What is the schwa sound in upon?

The schwa sound in "upon" is the short 'u' sound represented by the "u" in the word. It's a very common sound in English and is often represented by the letters "a", "e", "i", "o", or "u" in different words.

Here's how it works:

* Schwa is a vowel sound that is short, unstressed, and sounds like a very short "uh" sound.

* In "upon", the stress is on the first syllable, "u". This makes the second syllable, "pon", unstressed.

* Because the "o" in "pon" is unstressed, it makes the schwa sound.

So, the schwa sound in "upon" is the "u" sound in "pon".