Early in Babel, in between the masturbating Moroccan boy, sleeping tots in California and the hormonal deaf-mute Japanese teenage girl, Cate Blanchett asks Brad Pitt “Why are we here?”

Thanks to Babel’s star power, incoming freshmen will sign up for writer Guillermo Arriaga and director Alejandro Gonzalez Iñarritu’s latest class in cosmic-karmic contemplation. But with such an obnoxiously basic lesson plan (her question is geographical and existential!), people will await the drop date — which comes a painfully long two-plus hours from that point in the film.

So maybe it’s a good question, Cate. Why are we here?

Maybe because any upperclassmen in the room expect fierier, fiercer filmmaking from Arriaga and Iñarritu, who collaborated on Amores Perros and 21 Grams — both incendiary human dramas that leapt from the screen into your heart and mind.

Babel barely has the energy to sit up and wave. It continues a sad trend of beautifully filmed adult dramas using a lot of running time and big names to say not much at all, and it makes the overrated Crash look like a masters thesis in race-relations. Arriaga and Iñarritu reportedly have severed their creative relationship. Given Babel, it might be for the best.

A Biblical reference in their title — the tower erected by humanity to brag about reaching heaven that God scuttled by creating different languages to confuse its builders — allows a global movie. And if Iñarritu achieves anything, it’s a jerky sense of mood and tone to yank the viewer from one locale to the next — desolate Moroccan deserts, the warm soft glow of a family home in California, pulsing nightclubs in Tokyo, harsh lights of a border-patrol booth at the Mexico-United States line.

Still, the movie feels as small as Luxembourg — like a first draft dragged from a drawer and caked with dust that got blown off when big names showed interest.

As before, Arriaga and Iñarritu concern themselves with how humans are connected around a seemingly circumstantial event. Here, it’s a gunshot, fired by Moroccan brothers attempting to outdo each other with a rifle their goat-herding father purchased to kill predatory jackals.

One brother’s bullet hits a tour bus, shattering the shoulder of American passenger Susan (Blanchett), on a somber vacation with emotionally distant husband Richard (Pitt).

This scenario briefly capitalizes on the horrors of a mortal wound in a remote area before falling into melodrama. Pitt weeps and runs his hands through his salt-and-pepper hair in frustration while a pale Blanchett bleeds, urinates and smokes Moroccan herb to ease her pain.

Back at Susan and Richard’s California home, Mexican nanny Amelia (Adriana Barraza) watches their young children (Elle Fanning and Nathan Gamble). Susan’s medical crisis delays the couple’s return, which was to happen before Amelia was due at her son’s wedding in Mexico.

Unable to offload the kids, she decides to take them along — an idea obviously bound to turn bad before obvious foreshadowing of pistol fire and decapitated chickens. Both come at the hands of Amelia’s nephew, played by Gael García Bernal, perhaps paying back the favor for American introduction in Amores Perros with a nothing role that literally disappears from the third act.

Barraza’s work is good, although undercut by manipulatively withheld character information, and at least Fanning is more restrained in shedding tears than her histrionic older sister, Dakota.

In Japan, deaf-mute Chieko (Rinko Kikuchi) struggles not only with blossoming sexuality, but her mother’s recent death. Chieko alternates between still introversion and frank expression, and her uncomfortable grip on her life and her sanity easily is the only vital story and performance here; Babel’s best, if potentially seizure-inducing, scene is her ecstasy-fueled experience at a club.

But, ever mindful of connecting threads, her father’s revealed to be a hunter, see …

Babel could somehow sidestep its mostly impenetrable characters if its plot bothered to at least distract with some jigs and jags. But it’s plodding and obvious throughout, the only true surprise coming from insultingly infantile stabs at geo-political commentary with Richard and Susan’s story.

Being diplomatic given the filmmakers’ past success isn’t worth it, given the irony that a story about communication breakdown so woefully fails to connect. Putting it bluntly, Babel is a bore.