This chapter aims to present a theoretical justification for reconsidering the role of the sentence as a key persuasive linguistic unit in predicting responses to marketing communications. It proposes the application of sentence importance ratings as a simple yet viable way of analyzing sentence-level effects in marketing communications. Sentence importance ratings adopt a reader-driven technique developed in psycholinguistic research that has previously been used to measure readers' understanding of the propositional structures of written texts. At the micropropositional level, complex sentences in which the structures of embedded clauses and noun phrases are the same have been shown to result in poorer comprehension than complex sentences in which clause and phrase structures differ. Although studies directly examining language's role in advertising encoding, comprehension, memory, and persuasion represent a very small portion of advertising and marketing communication research, psycholinguistic studies that manipulate the difficulty of comprehending particular words and phrase combinations in general texts are quite common.