This manuscript, by Dr. Erin Smolak, is based on her dissertation work in Margaret Friend‘s Infant and Child Development Laboratory. This study is concerned with processing speed and early vocabulary as predictors of later language outcomes in typically-developing children. In particular, it focuses on two different measures of processing speed: an online and an offline measure. The online measure outperformed the offline measure but neither accounted for as much variance in vocabulary at age four as decontextualized vocabulary (a measure developed in the lab and now adapted to several languages). It is concluded that stable word-referent associations in the first two years of life are of central importance to the establishment of strong productive vocabulary at age four. Additional work is currently underway, with Jon Helm, to better understand the nature of offline processing and its association with executive function. Dr. Smolak, a student in the JDP in Language and Communicative Disorders, completed her dissertation in summer 2019 and is currently a postdoctoral fellow at Boys Town National Research Hospital studying the role of processing speed in children with language delays.