It's no accident that Apple chose a yellow icon for its walkie-talkie feature. I dug out my old (2002ish) Nextel with PTT (push to talk). It was all the rage back then... :
Nextel chirp - YouTube
Child Of The 80s & 90s - Chirp sound of the Nextel made me feel so official | Facebook
nextel walkie talkie|TikTok Search
TOAN MAGAZINE — Throwback Thursday: Nextel/Boost Mobile Chirp...