Why is my cellphone microphone not working?

[Android Central Question]

Today, I discovered that my phone's microphone is not working because some of my callers as saying that they couldn't hear me. What should I do?

 

[methodman89]

Is it some or all? Make a a short video and speak. Play it back. How does it sound?

 

[Rukbat]

Do the ones who don't hear you hear you if you switch to speakerphone?

If it's only some, it's a carrier problem. If they all hear you on speakerphone, but not on the regular phone, it's either dist and dirt crammed into the mic hole (it's pretty tiny, so a fingerful of dust is a pretty solid sound insulator) [clean it out with a thin sharp wooden toothpick, a strong light and, depending on your eyes, a magnifying glass] or it's a bad mic.

(The video recording mic is usually the speakerphone mic, not the phone mic.)