We study the response to shear of a one-dimensional monolayer embedded between two rigid plates, where the upper one is externally driven. The shear is shown to excite "shearons", which are collective modes of the embedded system with well-defined spatial and temporal patterns, and which dominate the frictional properties of the driven system. We demonstrate that static friction, stick-slip events, and memory effects are well described in terms of the creation and/or annihilation of a shearon. This raises the possibility of controlling friction by modifying the excited shearon, which we exemplify by introducing a defect at the bottom plate.