kayak / kyack 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. 👇
kayak: (noun) a small canoe consisting of a light frame made watertight with animal skins; used by Eskimos. (verb) travel in a small canoe.
kyack: NA
kayak: k·AY·ae·k
kyack: NA
(Examples are Wikipedia snippets under the CC ShareAlike 3.0 license. Definitions drawn from WordNet.)