Japanese particles have been studied syntactically and semantically in connection with preceding words for constructing sentence, and studied in terms of predicate in connection with core meaning of the noun. However, the role of particles in the field of reading has not clearly been explained. This dissertation investigates the role of Japanese particles for L2 and L1 readers reading aloud through the following questions: (1) In what ways do L 2 and L1 Japanese readers miscue on particles? (2) Why do L2 and L1 Japanese readers elongate the phoneme of the particle? (3) How do L2 and L1 Japanese readers' eye movements show fixation points on particles? (4) How do L2 and L1's Japanese readers' miscues of particles relate to the L2 and L1 readers' eye movements? (5) How do L2 and L1 readers' fixation points on particles relate to elongation? (6) How do L2 and L1 Japanese readers' fixation points relate to miscues and elongation? Five L2 and four L1 readers read a Japanese story that included 121 particles. By looking at miscues, the results show the segmentation process using particles. This segmentation process minimizes the number of particle miscues. Substitution, omission, and insertion miscues occur in a complex manner because they are related to finding word boundaries. Elongation occurs as a process of prediction and confirmation for making sense. L2 readers use elongation with miscues more often than L1 readers. In eye movement research, L2 reader's miscues are more highly connected to eye fixation than are L1 readers' miscues. Eye fixation points and elongation are used for prediction and confirmation for making sense. However, L1 readers' miscues mainly consist of fixation without elongation. L2 readers use more particles while L1 readers use more flexible construction with the meaning of adjacent words playing an important role. Readers do not just fixate, but also elongate particles to get information. The result shows that readers use miscues on particles, elongation, and eye fixations as complex processes to construct a meaningful text.