Acrolect refers to the prestige sub-variety of a speech continuum, spoken by the educated speakers of the community and often serving as the official (or unofficial) standard for that particular language (Platt, 1980: 271).
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)