Born in Germany but raised in London, Forster was exposed to influential musicians at an early age. Her mother, Nora Forster, was active in London's bohemian scene in the 1960s and '70s, and as a result, the younger Forster's upbringing was flush with music.
progressive rock band Yes; Barry Gibb of the Bee Gees taught her how to play harmonica; and the late Joe Strummer of the Clash gave the teenage Forster her first guitar lessons.
In 1976, punk rock exploded in England, and after meeting Paloma Romero (better known as Palmolive) at a Clash gig, the Slits were born. Soon, the all-female band was opening for the Clash, crafting a sound that relied less on the anger and fury of their male counterparts and more on rhythm and open spaces.
"It came completely out of nowhere, this weird, self-taught organic thing," former Slits guitarist Viv Albertine would later recall. "As we became more aware, we didn't want to follow male rhythms and structures."
The early Slits music, best captured on their influential 1979 debut, "Cut," combined the spirit of punk — minus the screaming — with Jamaican dub rhythms.
That free-spirited ethos extended to the artwork of "Cut" too. On it, three members of the Slits appeared topless and covered with mud.
In its original incarnation, the Slits made two studio albums and broke up in 1982. Forster, who eventually settled in Jamaica, went on to found the New Age Steppers, and toured with a re-formed Slits starting in 2005; a third studio album, "Trapped Animal," was released in 2009.
Though the band never achieved the widespread fame of male punk groups, the spirit of the Slits was a strong influence on the feminist-punk Riot Grrrl movement.
Wrote former Sleater-Kinney guitarist Carrie Brownstein on NPR.com: "Not once did a Slits song cease to amaze me.... Not once did they fail to excite or inspire me, to make me a worshipper of rhythm, chaos and of attitude."
Forster is survived by her mother and three sons, Pablo, Pedro and Wilton.