Early literacy skills are essential for children's academic development. This research used a comprehensive approach that included observations, assessments, and interviews with children and educators from various kindergartens, which involved 1040 children and 99 teachers from 71 early childhood institutions. The comparison of difficulties in pronouncing letters was measured through observation and assessment of children's ability to recognize the shape and pronounce of letters using augmented reality digital flashcards with a companion application called KIDOPA. The results show that children have difficulty saying the letters b, d, m, w, p, q, n, u, x, and z while reading letters. These difficulties are linear with the teacher's understanding of the importance of teaching literacy to children.