The function of focus is to activate a set of alternatives, providing the locus for focus‐sensitive particles like only. In the past decade, psycholinguistic research has shown that listeners entertain a set of alternatives in online language comprehension, similar to the algorithm stipulated by Alternative Semantics. The purpose of the present review is to gain a comprehensive picture of the role of focus alternatives in utterance comprehension and interpretation. Specifically, we focus on how the processing of focus particles interacts with alternatives activated by focus. We show that focus marking activates a network of related concepts, but over time, only those that can be considered as focus alternatives in the relevant context of the utterance are retained in the mental representation of the discourse. Focus particles, in turn, increase the competition between the focused element and its alternatives during the initial stages of comprehension, helping contextual restriction of the set of alternatives. Overall, the studies presented in this review show that focus does not only guide a listener in determining which alternatives are relevant for the purpose of conversation, it also plays a fundamental role in the memory representation of a discourse.