The memory load is too great. Many many words are forgotten. Many spellings are confused. Pronunciation of new words remains a mystery to students until the teacher first reads the words. Dislike for English increases as the junior high school students experience continuing failure, shame and stress.
Writing is a way of recording and recalling spoken language's sounds and meanings.
Teachers sometimes get Japanese students to write in English, but the students, without English phonics knowledge, cannot later pronounce what they have written. So writing in English is not a memory aid for these students at all. Japanese students need a phonics method that breaks their reliance on using the Japanese script to write English words. Because many English sounds cannot be accurately portrayed in the Japanese script. As a result, many Japanese learners of English inject the sounds of the Japanese script into their spoken English, replacing the unique sounds of English with Japanese sounds.