wails / whales are similar-sounding terms with different meanings (referred to as homophones). To better understand the differences, see below for definitions, pronunciation guides, and example sentences using each term. 👇
wails: (verb) cry weakly or softly.
whales: (noun) any of the larger cetacean mammals having a streamlined body and breathing through a blowhole on the head. (verb) hunt for whales.
wails: w·EY·l·z
whales: w·EY·l·z
(Examples are Wikipedia snippets under the CC ShareAlike 3.0 license. Definitions drawn from WordNet.)