Early literacy individual growth and development indicators (EL-IGDIs) assess preschoolers' expressive vocabulary development and phonological awareness. This study investigated longitudinal change in EL-IGDIs using a large (N=7355), internet-based sample of 36- to 60-month-old United States preschoolers without identified risks for later achievement delays. There were three major findings. First, results identified sensitivity to longitudinal change for all three EL-IGDIs (i.e., Picture naming, Rhyming, and Alliteration). Second, results demonstrated age-related differences in growth rates between 3- and 4-year-olds, especially for Rhyming and Alliteration. Third, preliminary national norms were reported. Discussion highlights the need for research examining the sensitivity of EL-IGDIs for younger preschoolers. (Contains 5 tables and 3 figures.)