Give Spanglish credit for ambition. Exploring the American immigrant conflict between tradition and assimilation that has been addressed by Hollywood ever since The Jazz Singer, James L. Brooks' comedy drama hits some true and very funny notes. Sadly, the film's structure is a mess, as its screenplay fails to balance four separate plotlines and ultimately collapses under the weight.

Brooks, who collected an Oscar in 1983 for Terms Of Endearment and later made a successful comment with 1997's acclaimed, but overrated, As Good As It Gets, has never been Hollywood's most prolific director. Here, he launches his most thematically ambitious effort, but only intermittedly finds success.

It is the story of Flor (Paz Vega) and Christina (Shelbie Bruce), a Mexican mother and daughter, who arrive in Los Angeles and are soon embroiled in the internal dramas of the Clasky family, who hire Flor as their housekeeper. Adam Sandler stars as John Clasky, a successful, but neurotic, chef with two children and a wife (Tea Leoni), so over-the-top in her evil that she's practically a cartoon character. Joining them is Cloris Leachman, as Leoni's drunken mother, who walks off with every scene she's in.

The film has four separate plots (spoilers): the Flor/Christina relationship, the John/Deborah relationship, the John/Flor flirtation and the Deborah/Bernice relationship. Its major problem is that it concentrates too much on one to the detriment of the others. For example, one virtuoso scene with Sandler, Vega and Bruce goes on for so long that Leoni is left out of the film for what seems like half an hour. The Clasky's daughter Bernice (Sarah Steele), meanwhile, is established early on as the most interesting character in the movie and then disappears for about 45 minutes.

Indeed, the film's structural problems are myriad: we learn practically nothing about what makes Sandler's character tick, whether or not he's an alcoholic, or what his motivations are. Sandler and Leoni are given a young son who appears briefly in two scenes and we're left wondering why he's even in the movie. And another big problem is one common to Brooks's films: in key scenes, the dialogue sounds awkward and unnatural, undermining them considerably.

That said, the performances are impressive. Vega, in her first English-language film, gives a better bilingual performance than Penelope Cruz ever has. Sandler, no longer so novel in a non-comedic role, after Punch-Drunk Love, does what he can with limited material, while Leoni is convincingly scary, as a borderline psychotic. However, the best performances, aside from Leachman, are those of Steele and Bruce, as the teenagers.

Spanglish, while a welcome return to the multiplexes for Brooks, falls well short of what it attempts to accomplish.