SANFORD, Fla. -

Determined to begin jury selection on Monday for George Zimmerman's second-degree murder trial, a judge will hear remaining disputes on voice experts testifying on Saturday morning.

Zimmerman is in court, which began promptly at 9:30 a.m., wearing a dress shirt, gray sport coat and tie. The hearing is focused on the audio experts testifying about the screams heard in the background of neighbors' 911 calls.

The defense is first calling forensic speech/audio expert Dr. John Peter French from the United Kingdom, via video conference. When questioned about his experience, French said he's handled 5,000 cases and appeared in court 200 times, mostly for prosecution.

Attorney Don West then questioned French on how he analyzes a recording audio sample. As far as analyzing screaming, the features French said he looks for to identify the voice are accent, rate of speech, vowel sounds, and more.

French said it is difficult to do a voice comparison when someone is shouting and that you can't determine from someone's normal voice what they sound like when under severe attack.

"I've never come across a case in the 30 years of my career where anybody has attempted to compare screaming with normal voices," French said, adding that voice comparison with screams is "uncharted territory."

French said the 911 call in question is not suitable for comparison, saying it "wouldn't have gotten to first base."

The state has started to question French, who said he only needs a new syllables to exclude a voice source, depending on quality.

Zimmerman's lawyers plan to call at least three witnesses on Saturday who they hope will convince Judge Debra S. Nelson the science methodology the state's voice experts are using is flawed and inadmissible at trial.

The experts the defense is questioning are Tom Owen, the expert who excluded Zimmerman as the source of the screams in the 911 calls, and Dr. Alan Reich, the expert who said he hears Trayvon Martin saying "I'm begging you" in the background of the 911 calls.

"The words at the screaming level were almost entirely those of Trayvon Martin," Reich said on Friday when asked about his analysis of the 911 call from a witness the night of the shooting.

French said that he was "disturbed" by Reich's methodologies he testified to.

Owen said on Friday he used Zimmerman's voice from his reenactment video to try to match the screams on the 911 call, raising Zimmerman's voice in the reenactment video and looping the 911 call clip with the screams in order to make a long enough sample to analyze.

French opposed to Owen's methodology, saying it was," not acceptable in the wider scientific community."

Both Owen and Reich testified on Friday at the Frye hearing, as West challenged their methodologies, findings and qualifications as audio experts.

The defense could also ask Nelson on Saturday to bar prosecutors from using certain words during the trial, believing words such as "profiling," or "vigilante," or even "wannabe cop," to describe Zimmerman would create an emotional response in the jury.

Nelson did rule on Friday that Zimmerman's 6 p.m. curfew could be extended until 10 p.m. at the end of Friday's hearing, but said he is still not allowed to travel out of Seminole County except to his attorney's office. The state had objected to the motion, given prior issues with bond.

Zimmerman is charged with second-degree murder for fatally shooting 17-year-old Trayvon Martin during a struggle in a gated community where he lived. He is pleading not guilty, claiming self-defense.

Martin's family claim the cries came from the teen while Zimmerman's father has testified they were those of his son.