Piaget (1964) cited by E. L. Criswell (1989, pp. 35-36) developed the theory that children grow intellectually in stages:
From years 0 to 2, children explore their tiny environments, and through physical exploration, learn that objects exist and do not change from day to day. This is the sensorimotor stage. This is a period of motor action.
The way I see it, the time can be successfully used for the children of this age to learn the names of different familiar objects and people in L2. It is also possible to do that in more than one second or foreign language.
The period from age 2 to 7 years is called the preoperational period by Piaget (1964). During this time, the child learns that a word can stand for, or represent, an object. Thus, using language is an important advance during this period. Children at this level can identify things they see, and they learn what things do by touching them or otherwise directly experiencing them.
Chapman, Dollaghan, Kenworthy & Miller (1983) in their article Microcomputer Testing and Teaching of Verb Meaning: What’s Easy and What’s Hard? in Classroom Computers and Cognitive Science edited by A. C. Wilkinson (1983) and cited by E. L. Criswell (1989, p. 35) all point out that facts about the young child’s developmental level should influence design of CBI for children.
Children below the age of 3 can learn to touch a screen to indicate their choices directly, but keyboard entry, even when the keyboard is color coded to the screen is too difficult for children this young.