i+1

· from English

What does i+1 mean in language learning?

i+1 is Krashen's shorthand for input one step beyond your current level (i), challenging enough to stretch you but still understandable.

If input is at your level (i), nothing new is acquired; if it is far beyond (i+10), nothing is understood. The idea is intuitive but hard to measure precisely. In practice it means choosing material where you understand most, but not all.

Examples

A text where you know about 95 to 98 percent of the words; a podcast you follow without pausing every sentence

Kungfucius says: Not too easy, not too hard. Goldilocks would have made an excellent language learner.