Mesolect refers to the sub-variety of a speech continuum, spoken by speakers with some education or, in new varieties such as Singaporean English, by educated people for semi-formal purposes. (p. 274)
Basilect refers to the lowest sub-variety of a speech continuum, spoken by speakers of little or no formal education. In some new speech varieties such as Singaporean English it also be used by educated people for their colloquial speech.