There is a risk in plain language, especially if no one has asked you to clarify. In a US trial for witness tampering, Judge Richard Posner refused to ask the jury whether the accused had acted “corruptly”, meaning “with the purpose of wrongfully impeding the due administration of justice”. He said these words added nothing to the other elements of the offence. (He did ask the jury whether the accused had acted deliberately, intending to interfere with the State Department’s investigation). The jury found the accused guilty.
However, in 2002 Arthur Andersen had been convicted of the same offence, for shredding documents after the Enron scandal. That conviction was set aside by the US Supreme Court, because the jury had not considered whether Arthur Andersen had acted corruptly. So following that and other decisions, the court hearing the appeal from Judge Posner directed a retrial, saying he had left out an “essential” element of the offence. They rejected another ground of appeal, that the witness tampering statute was too vague to enforce, though they agreed that it “defies easy summary”.
(Being reversed on appeal is probably the worst a judge will suffer for making an unapproved translation. A much worse fate awaited William Tyndale, who translated the Bible into English in 1526, in defiance of church and state. He was hunted down, locked up, strangled and burnt. But it has been estimated that the King James Bible (1611) was at least 75% his (uncredited) work.)
United States v Edwards, No. 16-2253 (7th Cir 2017), 24 August 2017. Thanks to Mark Adler for this news.