LETTER NAMING, UPPERCASE AND LOWERCASE
For the first 6 - 8 weeks of Kindergarten - and depending on the incoming students' skills - the name of all the letters, upper and lower case, should be directly taught. The old 'letter of the week' approach is much too slow and fails to prepare students for the sound-symbol associations they will need to learn for reading and spelling.
Knowledge of letter names and fluency of letter naming in Kindergarten are among the best predictors of later reading success. Early Kindergarten students need daily experiences with hands-on manipulatives such as alphabet puzzles; shapes for letter building; or templates for matching wooden or plastic letter shapes. Alphabet arc activities are excellent for matching uppercase and lowercase letters, and for locating letters by name. See below for alphabet arc examples.
(LETRS, Lousia Moats & Carol Tolman)
...Nevertheless, newer and more relevant research has shown that letter names may play an important role in early literacy learning. Those confusions do occur, but more often the letter names facilitate the learning of letter sounds – because the names and sounds are usually in better agreement than in the confusing instances (Treiman, et al., 2008; Venezky, 1975) and letter names seem to be more effective than sounds in supporting learning early in the progression (Share, 2004; Treiman, 2001). One instructional study with preschoolers found that teaching letter names together with letter sounds led to improved letter-sound learning when compared to just teaching the sounds alone (Piasta, Purpura, & Wagner, 2010) – and this benefit was clearly due to the combination and not to any differences in print exposure, instructional time or intensity. Another study (Kim, Petscher, Foorman, & Zhou, 2010) found that letter name knowledge had a larger impact on letter-sound acquisition than the reverse, and that phonological awareness had a larger impact on letter-sound learning when letter names were already known.
Timothy Shanahan (2021)