Shaw once said, "England and America are two countries divided by a common language." The latter part of Artists Repertory Theatre's season has done much to prove the point, as evinced in its productions of Charlotte Jones' Humble Boy (just closed) and Joe Penhall's Blue/Orange (just opened). Though markedly different, each of these plays is clearly a product of its culture. Both continue to explore Britain's class barriers (though class is not the major theme in either), and both depend upon the subtlety of British thought and language to work. All of this is beyond ART's grasp.

No one can fault Allen Nause and company for a lack of taste. Humble Boy and Blue/Orange are among the finer plays that have been produced in Britain recently. But it's one thing to appreciate the plays aesthetically and quite another to do them justice in production. Where classic British understatement and irony are required, we get crass lapses into typical American behavior: telegraphing arms, face-making, sputtering and braying. The cast of Blue/Orange is somewhat better than the Humble Boy troupe, which typified ART's singular mix of amateur professionals with professional amateurs (the sole exception being Valerie Stevens).

Blue/Orange is a deviously clever three-hander, in which two white psychologists battle over a young black patient who may or may not be schizophrenic. Penhall's play is an exciting round of one-upmanship, with the three characters circling each other verbally, looking for a winning punch (the stage in the original London production suggested a boxing ring). Yet fencing might offer a sharper metaphor, as Penhall's lines are a series of parries and thrusts. Rather than the dull, brutal round of raised voices that director Pat Patton has slapped together, the play needs to be performed dexterously with killing smiles and undertones.

The issue of race in Britain is the primary theme of Blue/Orange, though Penhall is not interested in any simplistic black/white conclusions. Is the young black man, Christopher (Bobby Bermea), insane? Perhaps, but it's also possible that his behavior is explicable given the racist environment within which he exists; this is the battle between his two doctors, the lower-middle-class Bruce (Ryan Lee) and the upper-middle-class Robert (Shelly Lipkin).

The inherent racism of the two doctors (and their class loathing for each other) creeps out in different ways, though their arguments for and against Christopher's release back out into the community have the distinction of being reasoned, and the audience finds itself first siding with one, then the other. And here's where Penhall delivers the coup de grace: In identifying with Christopher's captors, we (the predominantly white audience) are implicated. We are forced (if the play is done right) to confront, inevitably, our own racism. In Patton's "black/white" staging, Bermea's Christopher is obviously crazy and so becomes a cipher, while the pitched, one-note debate of Lee and Lipkin becomes a drone. All is finally lost in translation.

Artists Repertory Theatre at the Interstate Firehouse Cultural Center, 5340 N Interstate Ave., 241-1278. 8 pm Tuesdays-Saturdays, 2 and 7 pm Sundays. Closes May 29. $15 (students)-$35.