IPA: /ˈproʊtəˌtaɪpəl/
KK: /ˈproʊtəˌtaɪpəl/
Relating to an original model or first example of something from which others are developed.
The designer created a prototypal version of the new smartphone to test its features.
Prototypal is formed from "proto-" (from Greek "protos", meaning first) and "typal" (from Greek "typos", meaning model or type). The word refers to something that serves as a first model or example of a particular type.
Think of 'first' ('proto-') and 'model' ('typal') to remember that 'prototypal' means the first example of a type.
No commonly confused words.