The notional-functional approach in ESL is a way of structuring a syllabus around "notions," real-life situations in which people communicate, which are further broken down into "functions," specific aims of communication.
When designing a lesson, teachers in TESOL often choose a real-world situation as their "notion," and choose corresponding functions to teach to prepare students to communicate in that situation in the lesson. For example, a lesson might be about how to buy something at a shop, in which case its notion is shopping and one of its functions might be asking prices.
Functions often lend themselves naturally to specific grammatical patterns or common expressions. In the shopping example, one expression might be the question "how much is this (singular noun)?"
|a superior giving advice||preparing to give advice||Do you have a moment?||2|
|a superior giving advice||giving advice||you should (verb)||2|
|a superior giving advice||giving advice||it would be a good idea to (verb)||3|
|a superior giving advice||giving advice||you might want to think about (verb -ing)||3|
|a superior giving advice||concluding advice||Thank you for your attention to this.||2|
|customer to shopkeeper||getting attention||Excuse me.||1|
|customer to shopkeeper||asking a price||How much is this (singular noun)?||1|
|customer to shopkeeper||asking a price||How much are these (plural noun)?||1|
|customer to shopkeeper||buying||I'll take this.||1|
|customer to shopkeeper||buying||I'll take these.||1|
|customer to shopkeeper||negotiating||It seems a little expensive.||2|
|customer to shopkeeper||negotiating||That sounds a little high.||2|
|customer to shopkeeper||negotiating||Could you give me a discount?||2|
|customer to shopkeeper||refusing to buy||I'll think about it.||1|
|considering options||suggesting an option||Maybe we should look at (verb).||2|
|considering options||making a choice||Let's go with (noun).||2|