t have reached a cognitive level which allows for the acquisition of the new concepts. "You'll get over it!", for instance, implies a conceptualization of time, sensory perception, transience or ephemerality, and of self. A four-year old normally has no conception of mortality in L1 and is not likely to acquire it in L2. "You'll get by!" has an equivalent in Brazilian Portuguese, but may be conceptually alien to the Japanese mind and mores.
Timing the learning event, therefore, depends on cognitive, affective, and social development and maturity, which, normally, go with chronological age. It also depends on the nature and level of already acquired L2 concepts and forms: If "I do" has been mastered, "I don't" will come easily. Timing is directly related to the nature, forms, and levels of teaching and learning strategies which have been used successfully or imperfectly. It depends on the degree of literacy achieved in L1 and/or L2: even though the Japanese script (L1) is wholly different from that of English, the child who can write Japanese to any degree has at least mastered the concept of scripting, of translating thoughts and words into graphic symbols.
To the child who has not learned to write in Japanese, the approach to English scripting will be novel and suffer no interference from L1: if the learning process is made enjoyable, English scripting will be likened to drawing. Note, however, that writing in the Roman alphabet demands quite a different conceptual approach than writing in the ideographs of kanji. Hence, the difficulty for the Japanese is not so much to learn the symbolic script of English, but to learn to abandon the thinking process involved in translating thoughts into discrete holistic graphic symbols and to acquire the thinking mode needed to translate thoughts into linked cursive forms which are meaningless by themselves. If the child has already gained some mastery of hiragana and katagana, which are nat...