plain
You'd have no trouble understanding his point if he'd written the article in plain English!

spoken, written
conversational
They taught conversational English to a group of Japanese students.

accented (esp. AmE)
He spoke in heavily accented English.

American, British, Indian, etc.
China
African American Vernacular, Black
BBC, the Queen's
proper
pidgin
Early, Middle, Modern, Old

English is used with these nouns:
accent, breakfast, dialect, dictionary, expression, fare, mustard, origin, settler, spelling, subtitle, tradition, translation, usage