A study investigated the effects of second language (L2) acquisition age, length of L2 exposure, and gender on bilingual coding, and examined whether the bilingual dual coding effect in incidental recalls would be the same as in Indo-European languages. The bilingual dual coding hypothesis proposes that the individual's image system and the two verbal systems corresponding to the two languages in question are functionally independent but partly interconnected. Subjects were 47 female and 17 male balanced Japanese-English bilingual high school students at an Osaka (Japan) school for children returning from periods abroad. They were presented with pictures to be labeled in English, Japanese words to be translated into English, and English words to be copied. Later, without warning, they were tested to recall the generated English words. Results support the bilingual dual coding hypothesis, with no gender effects observed. Onset age of L2 acquisition was found to be significant. It is concluded that the theory is generalizable across bilinguals in both Indo-European alphabetic languages and in this alphabetic/non-alphabetic language combination, and also in child and well as adult bilinguals. Contains 97 references. (MSE)