I have an iPhone 12 Pro, I have been told that sometimes my voice sounds like a robot. Is this a speaker issue?

The person receiving your phone call is telling you that your voice sounds like a robot. This means that the issue may be with your microphone and not your speaker. This may also have something to do with a bad cell connection / service. You can address the microphone portion of the issue by having your iPhone 12 Pro examined at the Apple Store or at an Authorized Service Center. Your iPhone 12 Pro should still be under Apple’s 1YR Limited Warranty. Take advantage of it and have it examined.

If there are no hardware issues found on your iPhone then work with your cellular service provider to discuss service issues.

Axel F.