The term “immersion” is used in two very different ways in educational discourse. In the
first sense, immersion programs are organized and planned forms of bilingual education
in which students are “immersed” in a second language instructional environment with
the goal of developing proficiency in two languages. First language instruction is
typically introduced within a year or two of the start of the program and forms an integral
part of the overall plan. In its second sense, the term “immersion” refers to the immersion
of immigrant or minority language children in a classroom environment where instruction
is conducted exclusively through their second (or third) language (frequently the
dominant language of the society or a global language of wider communication). The
intent is to develop proficiency in the language of instruction. Such programs vary in the
amount of support they provide to enable students to acquire proficiency in the language
of instruction—in some cases extensive support is provided by specialist language
teachers but in other cases students are left to “sink or swim.” This second sense of the
term “immersion” reflects popular usage but, as described below, is diametrically
opposed to the conceptualization of immersion education within the educational research
community. In the remainder of this paper, “immersion education” will be used to
describe the first sense of the term—a planned program aimed at bilingual
development—while “immersion” or “submersion” will be used to refer to the exclusive
use of students’ second language (L2) as a medium of instruction with the goal of
developing proficiency only in the language of instruction.