Spanish

Spanish is a secondary language of the UNSC. Having its roots in Latin, Spanish bears many similarities to English and is used in various places throughout the UNSC, but has seen diminishing use due to the UNSC-wide adoption of English as its primary language.

Spanish is spoken mostly in areas where it saw prominence in earlier eras, such as Latin America and Havana. Many members of the UNSC Marine Corps speak Spanish, including Corporal Perez and Private Mendoza. However, they also speak fluent English, as well. This would seem to imply that Spanish is still widely used.