pica / pika 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. 👇
pica: (noun) an eating disorder, frequent in children, in which non-nutritional objects are eaten persistently. (noun) magpies.
pika: (noun) small short-eared burrowing mammal of rocky uplands of Asia and western North America.
pica: p·AY·k·ah
pika: NA
(Examples are Wikipedia snippets under the CC ShareAlike 3.0 license. Definitions drawn from WordNet.)