Simplify the following text for a Grade 8 native English-speaking person.
Original: Nesta Robert `` Bob '' Marley , OM ( 6 February 1945 â `` 11 May 1981 ) was a Jamaican singer-songwriter and musician .
Simplified: Robert Nesta `` Bob '' Marley ( February 6 , 1945 - May 11 , 1981 ) was an important Jamaican musician in the 1970s and 1980s .