An ELT Glossary : An Exponent

Definition : A language item which can be used to express a specific function

Examples : 

  • Why don't you ... and Shall we...  are exponents of making suggestions,  
  • Do you think you could possibly... and Would you mind... can be used to make a request.
  • I'm really sorry about... and I can't tell you how sorry I am about... can be used for the function apologising.
  • I think you should... and If I were you, I'd... can be used to give advice
  • I'll... and Would you like me to... can be used to offer help

Related Reading 

Finocchiaro and Brumfit, The Functional- Notional Approach, OUP