Overview of Second Language Acquisition Theory

An understanding of second language acquisition can improve the ability of mainstream teachers to serve the culturally and linguistically diverse students in their classrooms (Fillmore & Snow, 2002; Hamayan, 1990). While significant professional development is necessary to gain a full understanding of second language acquisition theory, some key concepts can be quickly understood and applied in the classroom.

Current theories of second language acquisition are based on years of research in a wide variety of fields, including linguistics, psychology, sociology, anthropology, and neurolinguistics (Freeman & Freeman, 2001).

One concept endorsed by most current theorists is that of a continuum of learning—that is, predictable and sequential stages of language development, in which the learner progresses from no knowledge of the new language to a level of competency closely resembling that of a native speaker. These theories have resulted in the identification of several distinct stages of second language development. These stages are most often identified as:

Stage I: The Silent/Receptive or Preproduction Stage: This stage can last from 10 hours to six months. Students often have up to 500 receptive words (words they can understand, but may not be comfortable using) and can understand new words that are made comprehensible to them. This stage often involves a silent period during which students may not speak, but can respond using a variety of strategies including pointing to an object, picture, or person; performing an act, such as standing up or closing a door; gesturing or nodding; or responding with a simple yes or no. Teachers should not force students to speak until they are ready to do so.

Stage II: The Early Production Stage: The early production stage can last an additional six months after the initial stage. Students have usually developed close to 1,000 receptive/active words (that is, words they are able to understand and use). During this stage students can usually speak in one- or two-word phrases, and can demonstrate comprehension of new material by giving short answers to simple yes/no, either/or, or who/what/where questions.

Stage III: The Speech Emergence Stage: This stage can last up to another year. Students have usually developed approximately 3,000 words and can use short phrases and simple sentences to communicate. Students begin to use dialogue and can ask simple questions, such as Can I go to the restroom? and are also able to answer simple questions. Students may produce longer sentences, but often with grammatical errors that can interfere with their communication.

Stage IV: The Intermediate Language Proficiency Stage: Intermediate proficiency may take up to another year after speech emergence. Students have typically developed close to 6,000 words and are beginning to make complex statements, state opinions, ask for clarification, share their thoughts, and speak at greater length.

Stage V: The Advanced Language Proficiency Stage: Gaining advanced proficiency in a second language can typically take from five to seven years. By this stage students have developed some specialized content-area vocabulary and can participate fully in grade-level classroom activities if given occasional extra support. Students can speak English using grammar and vocabulary comparable to that of same-age native speakers.

Understanding that students are going through a predictable and sequential series of developmental stages helps teachers predict and accept a student’s current stage, while modifying their instruction to encourage progression to the next stage. (For examples of instructional strategies explicitly tied to language acquisition stages, see this table.)

A concept endorsed by most language acquisition theorists is Stephen Krashen’s comprehensible input hypothesis, which suggests that learners acquire language by intaking and understanding language that is a little beyond their current level of competence (Krashen, 1981, p. 103). For instance, a preschool child already understands the phrase Get your crayon. By slightly altering the phrase to Get my crayons, the teacher can provide an appropriate linguistic and cognitive challenge— offering new information that builds off prior knowledge and is therefore comprehensible (Sowers, 2000). Providing consistent, comprehensible input requires a constant familiarity with the ability level of students in order to provide a level of input that is just beyond their current level.

Research by Merrill Swain and others has extended this concept to include comprehensible output. According to several studies, providing learners with opportunities to use the language and skills they have acquired, at a level in which they are competent, is almost as important as giving students the appropriate level of input (Pica et al., 1989, 1996; Swain & Lapkin, 1995).

Krashen’s Affective Filter Hypothesis is another concept that has found wide acceptance with both researchers and ELL instructors (Krashen, 1981; Krashen & Terrell, 1983). This theory suggests that an individual’s emotions can directly interfere or assist in the learning of a new language. According to Krashen, learning a new language is different from learning other subjects because it requires public practice. Speaking out in a new language can result in anxiety, embarrassment, or anger. These negative emotions can create a kind of filter that blocks the learner’s ability to process new or difficult words. Classrooms that are fully engaging, nonthreatening, and affirming of a child’s native language and cultural heritage can have a direct effect on the student’s ability to learn by increasing motivation and encouraging risk taking.

Another theory that has directly influenced classroom instruction is Jim Cummins’s distinction between two types of language: basic interpersonal communications skills (BICS) and cognitive academic language proficiency (CALP). Research has shown that the average student can develop conversational fluency within two to five years, but that developing fluency in more technical, academic language can take from four to seven years depending on many variables such as language proficiency level, age and time of arrival at school, level of academic proficiency in the native language, and the degree of support for achieving academic proficiency (Cummins, 1981, 1996; Hakuta, Butler, & Witt, 2000; Thomas & Collier, 1997).

Later, Cummins expanded this concept to include two distinct types of communication, depending on the context in which it occurs:

Context-embedded communication provides several communicative supports to the listener or reader, such as objects, gestures, or vocal inflections, which help make the information comprehensible. Examples are a one-to-one social conversation with physical gestures, or storytelling activities that include visual props.
Context-reduced communication provides fewer communicative clues to support understanding. Examples are a phone conversation, which provides no visual clues, or a note left on a refrigerator.


Similarly, Cummins distinguished between the different cognitive demands that communication can place on the learner:

Cognitively undemanding communication requires a minimal amount of abstract or critical thinking. Examples are a conversation on the playground, or simple yes/no questions in the classroom.
Cognitively demanding communication, which requires a learner to analyze and synthesize information quickly and contains abstract or specialized concepts. Examples are academic content lessons, such as a social studies lecture, a math lesson, or a multiple-choice test.
Understanding these theories can help teachers develop appropriate instructional strategies and assessments that guide students along a continuum of language development, from cognitively undemanding, context-embedded curricula, to cognitively demanding, context-reduced curricula (Robson, 1995).

A basic knowledge of language acquisition theories is extremely useful for mainstream classroom teachers and directly influences their ability to provide appropriate content-area instruction to ELL students. It is especially important in those schools or districts where limited resources result in little or no instructional support in a student’s native language. In these sink-or-swim situations, a committed mainstream teacher with a clear understanding of language acquisition can make all the difference.