Presumably Steve Koren watched “Liar Liar” a few hundred times before penning “A Thousand Words,” a long-on-the-shelf Eddie Murphy vehicle that’s finally seeing the light of day. It actually dates from the comic’s most dismal period, but it’s not quite as bad as his two other collaborations with director Brian Robbins, “Meet Dave” and “Norbit.” Of course, that’s damning with the faintest of praise.

The picture is a strenuously warmhearted fantasy that casts Murphy in a part that seems entirely too suited to him—as a motor-mouthed literary agent named Jack McCall, who doesn’t bother to read manuscripts but loves making big deals. His wife Caroline feels that he’s not sufficiently devoted to her and their young son, and Jack is himself concerned that he’s losing touch with his widowed mother Annie (Ruby Dee), who’s suffering from dementia and confuses him with his father when he visits at her nursing home.

At the moment Jack’s out to sign a guru named Sinja (Cliff Curtis) to a book deal and makes extravagant promises to get his signature. Unfortunately, during their conversation he cuts himself on a tree in the fellow’s garden, and the thing suddenly reappears in McCall’s own backyard. It soon becomes apparent that it loses a leaf with every word Jack speaks, and Sinja opines that his soul has become conjoined with it, which means that when the tree loses its last leaf and dies, so will he.

The rest of the movie consists of McCall learning what’s really important in life while struggling not to talk and shorten his days. It’s occasionally amusing to see the formidably verbose comedian grimace and mug as he tries to remain silent even when prodded by others, but it’s an act that even he finds difficult to sustain. Luckily help is at hand from a couple of other cast members. One is Davis, whose performances as the smoothly imperturbable Sinja is a nice contrast to Murphy’s hyperactivity. The other is Clark Duke as McCall’s nervous, eager-to-please assistant. He manages to keep a routine that could easily have gone stale fresh throughout.

The same, unhappily, can’t be said for Washington, who makes Jack’s wife a surprisingly pushy and unsympathetic person, or Dee, whose wounded nobility gets tiresome after awhile. Nor can Allison Janney do much with the role of McCall’s hardbitten boss.

But the weakness on the distaff side is mild compared to the script’s inclination to slip from good-natured slapstick into cruder stuff. The most egregious example comes in an episode set in a hotel where Caroline has invited Jack to sex up their life together again. The bedroom scene alone between the couple is likely to make you queasy, but the makers add to it a few homophobic moments involving another guest that are absolutely cringe-inducing. Why they would have thought this stuff appropriate in a movie that’s obviously directed toward a family audience is a mystery.

“A Thousand Words” is technically proficient, though the look Robbins and cinematographer Clark Mathis prefer is of the sitcom style, colorful and synthetic. But while not descending to the level of Murphy’s worst work—“Pluto Nash” still stands unchallenged—it’s a bland, negligible example of the ‘becoming a better person through magic’ scenario, and would have been better left to collect dust on the unreleased list.