Speech Expert: Trayvon Martin Screaming for Help in 911 Call Is 'Imaginary Stuff

Defense attorney Don West, center, addresses the court as defense attorney Mark O'Mara, left, and defendant George Zimmerman listen, in Seminole circuit court during a pretrial hearing, in Sanford, Fla., Saturday, June 8, 2013. Zimmerman has been charged with second-degree murder for the 2012 shooting death of Trayvon Martin. (AP)

A speech expert for George Zimmerman's defense called it "imaginary stuff" to claim that slain Florida teenager Trayvon Martin can be heard begging for help in 911 audio.

George Doddington refuted analysis from a state witness who testified that he detected Martin screaming "I'm begging you" on a 911 call.

"That's imaginary stuff," Doddington said during a pretrial in Sanford, Fla. Friday, calling the methodology to detect the audio -- using another recording of Martin's voice -- "absurd," ABC News reported.

George Zimmerman claims he acted in self-defense when he fatally shot the unarmed teenager last year; Martin's family says he was killed in cold blood by a man who racially profiled him.

Both sides are fighting over the screaming captured on the 911 audio. If it's determined to belong to Martin, it could indicate Zimmerman was the aggressor, but if it's determined to be Zimmerman, it could mean he was fighting for his life, as he has claimed.

Jury selection in the second-degree murder trial begins Monday, more than 15 months after the shooting that ignited racial tensions and set off protests throughout the country.