Speech Debelle, Queen Elizabeth Hall, London

Hip-hop, but not as we know it

A few months ago, Speech Debelle was the best kept secret of label Big Dada, and judging by your own loyalties (or perhaps lack of) to hip-hop music, she was either the genre's great redemption or a welcome distraction from the current reign of urban-pop. Then came the Mercury Prize nomination for her debut album, Speech Therapy, and with that an extra push from Big Dada and a flurry of commendations from critics and social observers alike, all firmly placing their bets on the unassuming south London MC who's now officially crossed over into the next best thing category, thanks to her rags-to-potential-riches story of living in a hostel, cavorting with drug dealers and making it safely to the other side to pursue a music career.

When you pit the 26-year-old up against the few British female rappers who have attempted to charm the mainstream, Speech emerges as the strong-silent type, less concerned with establishing her brand and the various connotations of her chosen occupation than the fem-cees who either pretend to be men-cees or brandish their sexuality with the ferocity of their freshly manicured talons. The biggest difference is that she has yet to be embraced by the very urbanistas who quickly rallied around former Mercury Prize winner Ms Dynamite and Estelle at the heights of their acclaim, and with her recent comment of not being "black enough" to be played on urban station Choice FM still ringing around uncomfortably, it's not surprising then that the bulk of the audience at this free gig are white, some audibly Speech converts, the rest curious spectators. They sit at tables and on the ground, a greater indication that the rapper's music sits neatly in that spoken-word/jazz sub-culture, where appreciation comes in the form on finger-clicks, mmms and ahhs, and the conservative hand clap.

She, on the other hand, is much less high-brow than her audience, and strolls casually onto the stage, wearing stretch jeans, a neon-printed T-shirt, trainers and her corn rowed hairdo half-done – evidence of her tomboyish and nonchalant attitude. She points out some former work colleagues with a humble wave, giggles when she mentions the Mercury accolade and then offers up "Searching" with a subtle prompt, diving into that now familiar intro "2am in my hostel bed, my eyes turned red, my belly ain't fed". Occasionally, she closes her eyes while her mellow three-piece band compliments her squeaky, staccato-driven flow and each of the songs are tacked with a funny anecdote of its origins. But it's when she's caught up in the poetic rhythm of her narratives that she's truly in her element and this is one of her better merits.

Nothing here conforms to a typical hip-hop show – there's no hypeman, no angst and not a whiff of narcissism. The only time she invites audience participation is on the anthemic, "Go Then, Bye", and to her credit, the crowd seem to be too self-conscious to join her in the break-up chant. It's not as if they can't relate.

Besides the hostel testimony, Speech's songs revolve around love and life. On the jovial "Working Weak" you can almost sense the silent high-fives when she sings "everyday, it is the same show, my boss is an a-hole." It's just a pity her playful delivery is occasionally lost in the poor acoustics of the Front Room in the Queen Elizabeth Hall. There are other idiosyncrasies too, such as the tiny lisp that causes her to stumble over some of her lyrics as she speeds through the set list – and when she invites Soweto Kinch on stage to sax along to "Buddy Love", you realise she's yet to completely conquer her shyness. But it's these things that make Speech so refreshingly real, so endearing, so justifiable of the hype – and so obviously a Mercury contender.