“threshold hypothesis: The belief among advocates of bilingual education that individuals with high levels of proficiency in two languages experience cognitive advantages in language skills and intellectual growth over those with low levels of proficiency in two languages, who have significant cognitive deficits.”
Excerpted from: Ravitch, Diane. EdSpeak: A Glossary of Education Terms, Phrases, Buzzwords, and Jargon. Alexandria, VA: ASCD, 2007.