How do people learn a language? This is a question that will impact any existing or prospective teacher whether they be teaching English or any other language. Over two articles I shall try to summarise some of the more impactful theories of Second Language Acquisition.

Input Hypothesis (Stephen Krashen)

Developed by Krashen in the 1970s as part of his studies into language acquisition it lays great importance on how much comprehensible input a learner is exposed to. Krashen felt that you could only measure competence in a language by gauging how well they understood input (language learners read or hear) as opposed to their productive output (what the learner says or writes). With regards to input Krashen believes in the simple formula.

i + 1 = comprehensible input level.

Essentially this means that teachers need to expose learners to language that is just a little higher than that which they can use themselves. Krashen also felt that this correct level of comprehensible input would provide enough examples of correct grammar that explicit and separate teaching of grammar wasn’t necessary. Krashen also pointed out that the mood of the learner or if they are stressed will impact upon the ability of the learner to acquire the language they are exposed to.

Output Hypothesis (Merril Swain)

Developed by Swain in the 1980s and published in the 1990s this could be seen as the opposite of the input hypothesis. Learners notice a gap between what they are able to say and what it is they actually want to say. The learner tries to produce the phrase or output that they want to say and then gauge its success based upon the feedback received from the other person that the student is communicating with. Reflecting on this feedback and the result of producing the language allows the learner to internalise and ‘digest’ the language used. However one criticism of this is that it relies on the learner to produce the language first but if they are anxious or worried about making a mistake they won’t produce the ‘output’ required in order to develop their learning of the target language.

Zone of Proximal Development (Lev Vygotsky)

Developed by Vygotsky in the 1920s and 1930s this was a theory that tied in with Vygotsky studies of ‘inner speaking’ or thinking to oneself and communicating out loud with others. Internal speech would often be more compressed and unintelligible to anyone other than the person holding the thought.

ZPD can be seen as a way to explain the relationship between a child’s learning and cognitive development. Vygotsky felt that with a suitable tutor a child could learn skills and complete tasks that they couldn’t complete independently without support. Development therefore will follow a child’s potential skill as opposed to its actual level of development. Some linguists have noticed that Vygotsky may have supported the idea of scaffolding as a child is given less and less support as a child starts to use language more independently much like you would scaffold help in a classroom setting as tasks become more free and the student has less support from the teacher but can utilise language they have already learnt.