We examine how the language of online reviews has changed over the past 20 years. The corpora we use for this analysis consist of online reviews, each of which is paired with a numerical rating. This allows us to control for the perceived sentiment of a review when examining its linguistic features. Our findings show that reviews have become less comprehensive, and more polarized and intense. We further analyzed two subgroups to understand these trends: (1) reviews labeled “helpful” and (2) reviews posted by persistent users. These trends also exist for helpful reviews (albeit in a weaker form), suggesting that the nature of reviews perceived as helpful is also changing. A similar pattern can be observed in reviews by persistent users, suggesting that these trends are not simply associated with new users but represent changes in overall user behavior. Additional analysis of Booking.com reviews indicates that these trends may reflect the increasing use of mobile devices, whose interface encourages briefer reviews. Lastly, we discuss the implications for readers, writers, and online reviewing platforms.