On January 6, 2011, Brent Smith of Shinedown spoke to The Pulse of Radio about their newly released video for their song “Diamond Eyes (Boom-Lay Boom Lay Boom) which was used on The Expendables trailer. When asked why the song has “Boom-Lay Boom-Lay Boom” as a subtitle, Smith explained:
“When we wrote the song, Sylvester Stallone said, ‘You have to repeat in some kind of a chant form or an anthemic form, I need it if you can to have it go ‘boom-lay boom-lay boom.” ‘Cause it’s based off of a poem called ‘The Congo’ that he based a lot of the premise of ‘The Expendables’ off of,” he said. “In that poem, between each paragraph, it goes ‘boom-lay boom-lay boom’ and then it goes to the next section of the poem.”
Here are links to The Congo, one to the Shinedown video and the original article.