CASLA is the abbreviation of
Computer aided language acquisition
CALT is the abbreviation of
Computer aided language testing
CALL 'tasks' include what may be otherwise referred to as games, exercises, activities, materials, even tests, and just 'ordinary use' of facilities like word processing.
CALLS sometimes are fully determined by the program, sometimes they are largely in the hands of the teacher or learner using the software.
CALLS may be done in class or at home, etc.