Or, as the Wikipedia Simplified Technical English Wikipedia mentions, use Plain English or Plain Language as non-aerospace alternatives:

> The US government's Plain English lacks the strict vocabulary restrictions of the aerospace standard, but represents an attempt at a more general writing standard.

https://en.wikipedia.org/wiki/Plain_English

> Modern corporations and academic organizations hire technical writers already trained to follow a simplified form of English that the layman reader can easily understand, known as plain language (PL).

https://en.wikipedia.org/wiki/Plain_language

And so we've looped back around OP’s “plain English” phrasing.