Everyone has favorites they can't rationally defend. "Big River," the musical based on "The Adventures of Huckleberry Finn," with the cornpone-sweet score by Roger Miller, is one of mine.

Deaf West Theatre, Joan Marcus The ensemble performs "Do You Wanna Go To Heaven?" from the first national tour of the Deaf West Theatre production of "Big River," based on "The Adventures of Huckleberry Finn." Click photo for larger image. "Big River" Where: PNC Broadway in Pittsburgh, Heinz Hall, Downtown. When: 7:30 p.m. today; 8 p.m. Fri.; 2 and 8 p.m. Sat.; 1 and 6:30 p.m. Sun. Tickets: $20-$60.50; 412-392-4900.

I see how corny William Hauptman's libretto is. And in spite of the sweetly plaintive score, bolstered with a stiff dose of gospel and blues, a lot of it is still, you know, "just" country-western.

But those are just matters of taste. More seriously, "Big River" doesn't seem to know its own heart, which is the slave, Jim, and his bond with Huck. For too long, Jim is kept off stage, with more time than necessary devoted to those cartoon scalawags, the Duke and the King.

No matter. Those objections are negated by the appeal of the music, with its half-dozen especially jaunty or heart-twisting songs, and above all by the deeply rooted parable about race relations and the lives we share.

This "my brother's keeper" theme is further intensified in this production from Deaf West Theatre, which features a cast half hearing-impaired. The whole show is spoken, sung and simultaneously rendered in American Sign Language, not by a signer at the side, but by the actors in the heat of the action, as hearing actors speak and sing for the others.

This creates an additional layer of expressive movement, even for those of us who don't know ASL. It's like tuning in to an additional language: You see the song being sung. The gulf thereby explored between deaf and hearing also mirrors Mark Twain's exploration of the deep national racial divide.

Part of the fascination is watching how it works. Usually, the speaker simply stands watching on stage, not taking focus, while the actor being spoken for mimes speech. But playing Twain, the narrator, Adam Monley, is free to wander at will, so it's easy for him to speak for Garrett Matthew Zuercher's Huck -- and, yes, Monley has different voices for the two.

The oddity of modern amplification actually helps, since when you can't tell where a voice is coming from, it can come from wherever it chooses.

Sometimes the voicer shares a scene, as when Gwen Stewart as Alice also speaks for Alice's distraught daughter. And there's the spooky effect of two Paps: when Huck's reprobate father looks accusingly in a mirror, out steps his double, and they pair up to give Huck twice as much of a hard time.

You begin to notice pairs throughout story and staging -- Huck and Jim, Huck and Tom, Duke and King, Miss Watson and Widow Douglas, the Robinson twins. Both sign, but usually one speaks and one is spoken for (you can hardly tell which), further paralleling Twain's theme of shared responsibility.

The central emotional line is Huck's discovery that shared humanity trumps status. He likes Jim, but he has to trust his instinct to reject society's categorization of him as property. That matches the story line, in which Huck and Jim float their raft through the heart of America, seeking freedom from slavery for Jim and from an abusive father or gentility for Huck.

Yes, this is yet another story in which a black serves as moral tutor, recalling a white to his better self. But what is a cliche elsewhere doesn't feel so in Twain, who created this American version of the noble savage. And David Aron Damane gives Jim a presence that suppresses objection. Even when Jim is silent or absent, he provides a moral context.

All this is so powerful it's almost irritating to put up with all the comic shenanigans of Tom Sawyer's escapades and the Duke and King's cons.

Directing and choreographing this mind-opening production is Jeff Calhoun, building expertly on the style used also by other deaf companies, such as the National Theatre of the Deaf, which made four Pittsburgh appearances in the '90s.

We quickly learn the device of shared speaking, and the vivid signing is a huge plus. What gives me trouble is the juiced-up acting style, which in the comic characters becomes antic cartooning. It matches the pleasant whine of the music and the drollery of Twain's humor, but sometimes it's just too frantic.

That may owe something to the size of Heinz Hall. There are 20 actors on stage, but "Big River" is a show that wants to be savored in a Broadway-sized house. Perhaps the acting has been pumped up to tour to bigger venues.

Ray Klausen's set doesn't have the lyricism of the 1985 Tony-winning Broadway design or the tour we saw in 1988, but its giant pages and images from Twain's novel harbor a flexible array of doors and windows that frame and advance the action. The small musical combo (seven, including a synthesizer) is big enough, with its banjo, fiddles and mandolins.

The energetic cast is a true ensemble, as the show demands, led by sprightly Huck, soulful Jim and genial Twain. The company includes Phyllis Frelich, a founding member of the National Theatre of the Deaf and memorable for her 1980 Tony for "Children of a Lesser God."

My favorite unexpected moment comes in a choral number near the end, when the singers suddenly stop and we get one more chorus in vibrant ASL alone. You hear it loud and clear.