Final answer:
The most common sound for /ow-ō-oo-ŭ/ is the short [oo] or [u] sound.
Step-by-step explanation:
The most common sound for /ow-ō-oo-ŭ/ is the short [oo] sound. For example, in words like 'book' or 'look', the sound 'oo' is pronounced as [ů].
In some cases, the short [oo] sound can also be spelled as [u]. For example, in words like 'bull' or 'full', the sound 'u' is pronounced as [u].
So, the short [oo] or [u] sound is the most common for /ow-ō-oo-ŭ/.