English for specific purposes research reveals that learners at a variety of levels experience difficulty reading science text, sufficient to impede their acquisition of science understanding. However, little research exists regarding subject-specific language styles or reading difficulty in Arabic. Difficulties with specialised language may seriously impede the development of physics understanding by Saudi students. Remedial attempts may remain ineffective unless informed by a better understanding of specific readability issues. This quantitative study involved 80 female Year 10 students studying science in two cities in Saudi Arabia (Jeddah and Abha). A specialised cloze test based on the mandatory physics textbook was developed to identify language features of the passage that participating students found difficult. Findings reveal that (a) these Saudi students experienced greater difficulty in reading their physics book (28% conceptually correct responses) than that suggested by earlier work with English speakers of similar age (62% conceptually correct responses); and (b) Saudi student difficulties with grammatical categories form a distinguishable pattern, but the pattern differs from that indicated by earlier work with English-speaking student.