This is a Voice icon. We've made it in iOS style, first introduced in iOS version 7 and supported in all later releases up until now (at least iOS 11). This style is based on thin two-pixel lines and is optimized for 50x50 px. Unlike other vector icon packs that have merely hundreds of icons, this icon pack contains 12,700 icons, all in the same style and quality.
The main part of the logo is made of two connected shapes. On the left is a triangle with slightly rounded corners, and connected to it is a triangle facing left but cut in half so that the two shapes together look like a speaker facing to the right. Two semi circular lines are coming out of the speaker and represent sound waves.