audience design refers to notion that speakers will take into account whom they are addressing and alter their speech style accordingly.

linguistic convergence is a process in which speakers change their speech to make it more similar to that of their hearer,

linguistic maintenance is a process in which speakers may choose not to converge, but instead to maintain their own variety.

linguistic divergence is a process in which speakers choose to move away from the
linguistic norms of their hearer in order to emphasise the difference between themselves and the person or people they are talking to.