Observing that a linguistically principled characterisation of standard English remains elusive, this chapter explores the indeterminacy surrounding standard English, as well as reasons why a broad consensus on what it comprises is challenging to achieve. This indeterminacy is particularly acute with regard to the concept of standard spoken English, where uncertainty has been exacerbated by the failure of the prescriptive grammatical enterprise to acknowledge systematic structural differences between written and spoken English as well as formal and informal speech. Although linguistic accounts stress that standard English is best conceptualised as an abstraction to which actual usage conforms to a greater or less extent, there remains a gulf between academic and public understanding of the standard language. This disconnect facilitates the perpetuation of obfuscatory ideologies which inform public discourse about standard English. These include tenacious beliefs in the infallibility of its norms and its putative superiority to non-standard varieties, which are routinely dismissed as ‘incorrect,’ ‘vulgar’ and ‘uneducated’, when not altogether discounted as English. Empirically accountable analyses of naturally occurring discourse furnish an indispensable corrective to highly idealised prescriptive accounts of usage, which often fail to capture many of the implicit regularities of actual speech.