Because Arabic and Chinese are relatively difficult languages for English speakers to learn, it tends to take a greater number of courses or credits of those language courses to reach a high level of proficiency, compared to languages like French or Spanish*. So the needed level of courses may be quite high for a student wanting to learn them to a high level of proficiency.
*Arabic and Chinese are DLI category IV languages where the DLI courses are 64 weeks, versus 36 weeks for DLI category I languages like French and Spanish: Languages Offered | Defense Language Institute Foreign Language Center . So it is likely that (for example) Spanish proficiency after 4th semester Spanish would be like Arabic proficiency after 7th semester Arabic.