Recent Research
Three key issues
The research is unambiguous in relation to three issues:
Time Needed to Catch Up
Conversational and Academic Proficiency Research studies since the early 1980s have shown that immigrant students can quickly acquire considerable fluency in the target language when they are exposed to it in the environment and at school but despite this rapid growth in conversational fluency, it generally takes a minimum of about five years (and frequently much longer) for them to catch up to native-speakers in academic aspects of the language.
Use of Primary Language Helps Students Learn English
During this period, especially for younger students, conversational fluency in the home language tends to erode. This is frequently exacerbated by the temptation for teachers to encourage students to give up their first language and switch to English as their primary language of communication; however, the research evidence suggests that this retards rather than expedites academic progress in English.
Implications for Instruction
The major implication of these data is that we should be looking for interventions that will sustain bilingual students' long-term academic progress rather than expecting any short-term "quick-fix" solution to students' academic underachievement in English.