The key difference between cultural diffusion and cultural assimilation is that cultural diffusion is the spreading of cultural traits from one group to another whereas cultural assimilation is the process in which a minority group or culture begins to resemble those of a dominant group.
Cultural diffusion and cultural assimilation are two concepts that describe the spread of culture. However, there is a distinct difference between cultural diffusion and cultural assimilation. In cultural diffusion, two or more cultures come together, and elements of both cultures start to mix together. However, in cultural assimilation, one minority group or culture become a part of a dominant culture by adopting the practices and norms of the new culture and forgetting the original culture.