It was not long ago that a State Department interpreter translated former President Carter's word "respect" with the Polish word for "lust." The incident inspired Ben Miller to write a comic opera on war and misunderstanding, and the premiere of "Ben" at Prince George's Publick Playhouse Saturday night was the final and by far the most satisfying offering of Operafest II.

The action of this bilingual one-acter begins appropriately with a language lesson and a bit of French and English lovemaking. There follows a summit arms conference, at which Ben's mistranslations lead to a declaration of war. There is also a wicked arms dealer, and a mysterious Alien Queen and chorus which turn out to be "from Mars or Jupiter . . . or within your heart." It is a sweet, sweetly liberal fairy tale; and of course it has a happy ending. Happy for all, that is, except for the arms dealer who then sings that "without war, sellers of arms can't make an honest living." w

The witty, even prosaic libretto is genuinely funny, and much of the music is early romantic as heard through modern laughter. It is scored for two pianos, cello and synthesizer. If at times the piano writing lacks the self-sufficient marvel of, say, Ned Rorem's "Bertha," there are always a mad momentum and humor which are no small victories.

Akim Nowak directed with speed and intelligence, never letting the action pause to chuckle over its own cuteness. William Huckaby's conducting was a wonder of strategy and wit. The young cast served the composer well, particularly tenor John Day as Ben and baritone Marvin Finnley as Le General. Gene Galvin brought a touching treble timbre to the coloratura fairy role of the Alien Queen.

"Ben" received a simultaneous premiere this week at the Opera Studio of the National Opera of Belgium.