Theatre: Umabatha: the Zulu Macbeth Globe Theatre, London

In Tom Stoppard's Dogg's Hamlet, the audience is confronted with a group of actors apparently speaking English - you see them building a stage, shouting "Plank", "Slab" and "Block" to one another, and it seems obvious that these are just ordinary words to describe the objects they are using. But it turns out that they are speaking an entirely new and foreign language that happens to be composed of English words. In this language "Plank" actually means "Ready", "Slab" means "OK" and "Block" means "Next". Some meanings are inverted entirely: a schoolboy's respectful "Good day, sir" comes out as "Useless git."

Something similar happens when you watch Shakespeare performed in a foreign language, although in this case it's not the words but the events and characters that seem misleadingly familiar. Umabatha, for instance, seems for the most part like a straight translation of Macbeth into Zulu terms. In Welcome Msoni's version, Macbeth becomes Mabatha, Macduff is Mafudu, Banquo is Bhangane; they wear animal skins, fight with spears and shields, live in kraals rather than castles, and the invading army by which Mabatha is finally defeated comes from Swaziland. Nudged along by helpful surtitles - just enough to keep you posted without distracting too much from the action - it's no trouble to follow the plot, and there are a number of moments when, although the language is unfamiliar, gesture and expression make it clear exactly what is being said: when Mabatha (having first gee'd himself up with what looks like a snort of cocaine) reaches for an invisible dagger, for instance, or when his wife, Kamadonsela, mimes tearing a child from her breast and dashing its brains out.

But, at other points, you can't help wondering whether things are really so straightforward. When the murderers set out to kill Banquo, is their exaggeratedly stealthy walk meant as a joke - it certainly raised a laugh on Monday evening - or is it simply a formalised expression of caution and guilt? Mabatha himself, in Thabani Patrick Tshanini's full-throttle performance, sometimes comes across as a clownish figure: is his discomfort meant to be amusing? In this world, do we assume that Bhangane's ghost is literally there, or is it an expression of Mabatha's guilt? Similar questions arise from any Macbeth; in this case, we have no way of answering them.

In some ways, Umabatha is more "authentic" than any modern Macbeth - Msoni and his athletic, dynamic cast manage to suggest vividly a warrior society, in which fighting prowess is not simply an admirable but incidental attribute, it is central to a man's identity. Not much modern British Shakespeare manages to integrate music and dance with the drama in the easy, thrilling way that this play does. In the end, though, it's not as an African take on Macbeth that you want to see it, but as an original play in its own right, which happens to have a rather similar plot. And on that level, in case you were wondering, it is unfailingly gripping and exciting, a triumph both for Msoni and for Mark Rylance's Globe.

Continues at the Globe to Sat (0171-401 9919)