Little information is available on d/Deaf and hard of hearing (d/DHH) learners' L2 development. Their limited auditory access may discourage them from taking standardized tests, highlighting the need for alternative ways of assessing their L2 development and proficiency. Therefore, this study suggests adopting processability theory, which demonstrates a universal order of L2 development. Interviews with d/DHH learners and their teachers were conducted to explore their current difficulties in regard to understanding their L2 development. Also, we conducted brief speaking tasks to suggest alternatives to testing the L2 development of learners who are d/DHH in comparison to typical literacy learners. The result showed d/DHH students' L2 developmental patterns are similar to those of typical hearing peers, suggesting that d/DHH students and hearing learners share difficulties in similar areas when learning English. Teachers highlighted the lack of appropriate English tests to determine the d/DHH students' L2 development.