Piasta, S. B., Purpura, D. J., & Wagner, R. K. (2010). Fostering alphabet knowledge development: A comparison of two instructional approaches. Reading and Writing: An Interdisciplinary Journal, 23(6), 607–626. https://doi.org/10.1007/s11145-009-9174-x
Preschool-aged children were randomly assigned to receive small group instruction in letter names and/or sounds or numbers (treated control). Alphabet instruction followed one of two approaches currently utilized in early childhood classrooms: combined letter name and sound instruction or letter sound only instruction. Thirty-four 15 minute lessons were provided, with children pre-and post-tested on alphabet, phonological awareness, letter–word identification, emergent reading, and developmental spelling measures. Results suggest benefits of combined letter name and sound instruction in promoting children’s letter-sound acquisition. Benefits did not generalize to other emergent literacy skills.