Communication is vital for social participation. However, communication often takes place under suboptimal conditions. This makes communication harder and less reliable, leading at worst to social isolation. In order to promote participation, it is necessary to understand the mechanisms underlying communication in different situations. Human communication is often speech based, either oral or written, but may also involve gesture, either accompanying speech or in the form of sign language. For communication to be achieved, a signal generated by one person has to be perceived by another person, attended to, comprehended and responded to. This process may be hindered by adverse conditions including factors that may be internal to the sender (e.g. incomplete or idiosyncratic language production), occur during transmission (e.g. background noise or signal processing) or be internal to the receiver (e.g. poor grasp of the language or sensory impairment). The extent to which these factors interact to generate adverse conditions may differ across the lifespan. Recent work has shown that successful speech communication under adverse conditions is associated with good cognitive capacity including efficient working memory and executive abilities such as updating and inhibition. Further, frontoparietal networks associated with working memory and executive function have been shown to be activated to a greater degree when it is harder to achieve speech comprehension. To date, less work has focused on sign language communication under |