My left speaker isn’t working but my right is

FYI...The iPhone 11 has one speaker on its bottom edge and one in the center of the notch. However, it's important to know that the grille located to the left of the Lightning port isn't a speaker like the grille located to its right. The left grille is a barometric vent that helps your iPhone 11 measure altitude. A microphone is also located in each grille.

There is no speaker on the left side. That is a microphone.