Topic drop in German: Empirical support for an information-theoretic account to a long-known omission phenomenon

German allows for topic drop (Fries 1988), the omission of a preverbal constituent from a V2 sentence. I address the underexplored question of why speakers use topic drop with a corpus study and two acceptability rating studies. I propose an information-theoretic explanation based on the Uniform Information Density hypothesis (Levy and Jaeger 2007) that accounts for the full picture of data. The information-theoretic approach predicts that topic drop is more felicitous when the omitted constituent is predictable in context and easy to recover. This leads to a more optimal use of the hearer’s processing capacities. The corpus study on the FraC corpus (Horch and Reich 2017) shows that grammatical person, verb probability and verbal infection impact the frequency of topic drop. The two rating experiments indicate that these diferences in frequency are also refected in acceptability and additionally evidence an impact of topicality on topic drop. Taken together my studies constitute the frst systematic empirical investigation of previously only sparsely researched observations from the literature. My information-theoretic account provides a unifying explanation of these isolated observations and is also able to account for the efect of verb probability that I fnd in my corpus study