has led Jennifer Jenkins to propose the Lingua Franca Core (LFC), a set of segmental features of pronunciation essential for learners to be understood by native speakers of English.

should be emphasized in countries belonging to the inner circle, according to Kachru’s classification of the English-speaking world.

has as its main goal to prepare learners to interact with native speakers of English from various dialects.

takes into account the characteristics of the interactions between non-native speakers (NNS) of English.