Historically, networks used different languages. Most modern unlocked phones are "universal" and support both, but older or budget models might be restricted to one.
While "unlocked" means the software restriction is removed, the hardware must still support the carrier's specific technology: if i buy an unlocked phone will it work
Carriers use specific radio frequencies (bands) to transmit data. For the best 4G or 5G coverage, your phone must have antennas for the exact bands your carrier uses. Historically, networks used different languages
Occasionally, carrier-specific features like Wi-Fi Calling , VoLTE , or Visual Voicemail may not work perfectly on an unlocked device if the carrier hasn't "certified" that specific model. How to Verify Before Buying Is Your Phone Compatible? Cellular Network bands carrier-specific features like Wi-Fi Calling
