Had Ryeisha Berrain not left a voice mail for producer DJ Blaqstarr when she was 15, she might never have met M.I.A. nor landed a plum record deal. “My older sister knew Blaqstarr,” says the soft-spoken Berrain, now 18, whose musical moniker comes from her childhood nickname, Rye Rye. “One time my sister was on the phone with him and he asked if I knew how to rap because he liked the sound of my voice. But I was being shy, so I said ‘No.’” Several days later, Berrain called up her sister’s friend with a few verses she’d recently written in hand. “He didn’t answer, so I rapped it on his answering machine,” she says.

Impressed by her rhymes and gritty staccato, Blaqstarr enlisted Berrain to rap on a track called “Shake It To The Ground,” which became a Baltimore club anthem and MySpace sensation. The track lured a key fan — the singer/producer/designer M.I.A. (aka Maya Arulpragasam) — to Baltimore to find Berrain, who was living with her mom and two sisters in Baltimore’s Chapel Hill housing projects. Berrain had never heard of the Sri Lankan indie darling. “Blaqstarr called me and said somebody wanted to meet me at the studio,” she says. “It was M.I.A. She was just like, ‘I’ve been looking for you for the longest time.’ And I was like, ‘What? Who is this lady?’ ” Arulpragasam quickly took on a multifarious role in Berrain’s life, influencing her sound and style.

Berrain’s new mentor invited her on tour, and they set out in 2007. Berrain opened for M.I.A. at shows in the U.K., Mexico and the U.S., all the while finishing up her high school degree from the road. Unlike other teen musicians, Berrain didn’t bring a momager or watchdog relative with her (“I’ve been a responsible person ever since I was younger.”). She credits Arulpragasam and crew with keeping her in line. “They were very overprotective,” says the rapper, adding, “[Maya] calls me her daughter.”