It's called th-uh schwa sound. It kind of sounds like a short U, th-uh, th-uh, th-uh.
它被称为 th-uh schwa 声音。听起来有点像短的 U、th-uh、th-uh、th-uh。
英语百科
Short U (Cyrillic)
Short U (Ўў; italics: Ўў) is a letter of the Cyrillic script.
The only Slavic language using this letter is the Belarusian Cyrillic script.
Among the non-Slavic languages using Cyrillic alphabets, ў is used in the Dungan language and in the Siberian Yupik language. It was also used in Uzbek before the adoption of the Latin alphabet in 1992.