Which linguistic feature did Duolingo incorporate into its 'streak' loyalty program that cognitive linguists attribute to its extraordinary 85% user retention rate?

Language plays a crucial role in how brands build customer loyalty programs. The terms, slogans, and linguistic features used in loyalty programs can significantly impact consumer engagement and brand perception. This trivia question explores how a major language-learning platform leveraged linguistics in their customer loyalty strategy to create one of the most successful engagement models in educational technology.

This is a live public trivia poll on AIPolls.Net. Vote and see real-time results.

Loss aversion framing (fear of breaking the streak)
Synesthetic metaphors (connecting language learning to physical sensations)
Recursive embedding (gradually increasing complexity of sentences)
Phonological reinforcement (rewarding proper pronunciation)