Comprehensible Input vs. Comprehensible Output

The topic for #langchat on Twitter was regarding ‘comprehensible input’ last Friday, April 25. Lots of discussions were generated. Practical strategies and insightful ideas were shared. Later, the topic was expanded to ‘comprehensible output’ and brought out more discussions.

Dr. Stephen Krashen stated that comprehensible input refers to messages that people understand when acquiring a second language. The message should be slightly above the learner’s current language level (i+1). According to Krashen’s theory of the second language, comprehensible input help learners to acquire a second language through meaningful interaction, which is different from learning a second language consciously through formal instructions. Many important researchers have clearly identified that second language acquisition can only occur when comprehensible language input is provided and understood by learners. 

Merrill Swain developed comprehensible output. As much as scaffolding is needed for comprehensible input, equal opportunities should also be created to develop students’ ability to respond and interact in the target language accurately and appropriately within a specific context and a safe learning environment. It’s part of the process of second language acquisition, using language for authentic and meaningful communication. According to Swain, there are three functions of output: (1) the noticing/triggering function; (2) the hypothesis-testing function; (3) the metalinguistic (reflective function). The negotiation of meaning plays an essential role in explaining this theory. Just as toddlers develop their language, they initially receive comprehensive language input. After receiving correct linguistic feedback through positive give-and-take interaction, they then begin to produce the language that can be understood. 

In order to investigate this topic more in-depth, I have come up with some guiding questions:

• How can teachers adjust the delivery of instruction to enable students to achieve a higher level of fluency and accuracy in the target language? 
• As teachers, how can we make input comprehensible to allow students to access meaning? 
• How can we plan lessons incorporating anticipated language needs that enable students to tackle the demands of the curriculum?
• What are the strategies that we can use for comprehensible output? 

We must bear in mind that comprehensible input is NOT equal to simplified instruction. It doesn’t mean that we always have to use lower-level vocabulary and grammar structures to help students understand the content. As mentioned above, the messages should be ‘i+1‘ (Krashen). Additionally, in my opinion, teachers need to take an apprenticeship approach to help students develop language skills at higher proficiency levels that native speakers can clearly understand. Comprehensible input and comprehensible output should be emphasized with balance and work hand in hand for an effective language acquisition process. 

I have put together a list of strategies that teachers might use when helping students acquire a second language.