What is second language acquisition (SLA)?
Second Language Acquisition (SLA) is the process by which people learn a new language, as well as the scientific discipline devoted to studying that process. A foundational approach to understanding SLA can be found in Stephen Krashen's theory, which is central to this field. Krashen's theory comprises five key hypotheses that collectively explain how individuals acquire a second language, often distinguishing between language learned in natural settings and formal educational environments. This theory offers insights into the process of language learning beyond the first language, addressing the nuances of acquiring additional languages. Here we look at the five hypotheses put forward by Stephen Krashen:
Table of Contents
The Acquisition-Learning Hypothesis
The Affective Filter Hypothesis
The Acquisition-Learning Hypothesis
Here Krashen posited that there are two different mechanisms by which we are able to develop language ability. The first is an unconscious process of absorption of the language in the way that most people are able to 'acquire' their native language. Krashen contrasted this with language learning, which involves the conscious activity of learning the language structures and rules, as is often the case in traditional classrooms. Krashen noted that the first appears more successful than the latter and we should therefore try to reproduce the conditions of 'acquisition' into the learning (classroom) environment.
The Monitor Hypothesis
The term 'monitor' is used as this is an editing function of the brain. The monitor will check previous knowledge against any utterance made and correct if needed. However in order for the editor to be of use there are three conditions which must be met. The editing function of the monitor will only happen when:
- The speaker has time to analyze what they have said, otherwise they will miss any mistakes.
- The speaker is focused on using the correct form of the language, otherwise the monitor is not triggered to correct.
- The speaker has knowledge of the rules, otherwise the monitor will not register that a mistake has been made.
Also read: How do ESL students learn best?
The Natural Order Hypothesis
As the name implies there is a natural order to the way we acquire/learn a language. Based upon empirical findings it is stated that learners typically acquire a languages' structure (grammar) in a predictable order. Whilst this may not be exactly the same order for the first and second languages acquired, there is a sequence present in both. Whilst it may be tempting to say if there is a natural order to what we acquire then we should teach in that order. This idea however has been rejected.
The Input Hypothesis
This is possibly the most important of the five hypotheses as it attempts to describe how we move from one level of language acquisition to the next. This is the first important point, the natural order hypothesis relates to acquiring the language not language learning (see the first hypothesis). According to Krashen we move from our current level of knowledge to a higher level by it being presented to us in a meaningful context. If our current knowledge is 'i' then we can move forward by looking at material that is at a level of 'i + 1'. Providing this new knowledge is not too far beyond our current understanding, we can discover its meaning if it is presented in a meaningful context with some need to understand it. This idea goes against the idea that we should learn a rule and then apply it. Krashen's input hypothesis suggests that we should present any new structure in a communicative context and solve its meaning in situ.
The Affective Filter Hypothesis
The final hypothesis relates to a barrier to learning. The affective filter is made up from internal and external factors which hinder our ability to acquire language. This idea was first posited by Dulay and Burt (1977).
In order for acquisition to be successful it is important that the students' affective filter is kept low. External factors which interfere with the acquisition process could include things like external noise around the classroom and noise (unrelated to the learning topic) inside the classroom. These distractions raise the affective filter. Internal factors that would raise the affective filter include high anxiety, low self-confidence and poor motivation.
Also read: Can I learn a foreign language while teaching English abroad?
