Wikipedia
Kovalchuk ( Russian, Ukrainian: Ковальчу́к), Kavalchuk ( Belarusian: Кавальчу́к), Kowalczuk ( Polish), also transliterated as a German adaptation Kowalchuk (in the North American diaspora), is a common East Slavic surname (one of the most popular in Ukraine). The Kovalchuk name extends back to before 1500 AD in the Kievan Rus.
Koval (Коваль) literally translates as forge or blacksmith. The suffix -chuk denoted either a son of, or an apprentice to a blacksmith. It is somewhat similar in commonality to English surname Smith. It is also cognate with very popular Polish surnames Kowalczyk and Kowalski.
In East Slavic Languages, the correct pronunciation would be ko-vahl-CHOOK, but for those living in the West, for example Ukrainian Canadians, the pronunciation ko-WAL-chuk is more common.