Many students who are English language learners have difficulty with reading and writing in English, even after they seem to be speaking the language fluently. This is in part because of limited vocabulary. Although they may have a large vocabulary when you consider all the words they know in their two languages combined, their English vocabulary may be less extensive than that of a native speaker. In addition, students who are quite fluent in conversational English, or the type of informal English used in everyday social situations, may still experience difficulty with the more formal “academic English” of the classroom.
Although your student seems to have developed a relatively high level of conversational fluency in English, it is not unusual for him to need extra help with written assignments, especially those that have a high language load. The Educators section of the Colorín Colorado Web site has lots of information on how to provide scaffolding for English language learners as they work to develop their language skills. Also check out the For Families section for articles in Spanish that you can share with your student’s parents to help them understand how to help their son.
Regarding the question of which language to use at home, research suggests that all children benefit from having a rich language environment at home, and for bilingual children, that often means an environment in which a language other than English is spoken. Encourage your student’s parents to spend time talking with their son and reading to him in whichever language they feel most comfortable. The skills he develops in his home language will provide a foundation for developing language and literacy skills in English.