In that conversation, Copeland called Savage "a liar." On Monday, Copeland said she had no fear calling Savage a liar and said the 2006 conversation was not serious.
Monday was the start of the defense in the trial, which began Feb. 4.
Savage, 38, is accused of committing or directing 12 murders while running a sprawling drug network. He is serving a 30-year term on trafficking charges but faces the death penalty if convicted of racketeering and murder.
Copeland, a schoolteacher with a master's degree in education, said she had been in a relationship with Savage since 1995.
"He's angry for you going to parties and not checking with him ahead of time," Assistant U.S. Attorney Steve Mellin said during his cross-examination. He called Savage's threats "stalking."
Mellin also questioned Copeland about events the night before the deadly Oct. 9, 2004, North Philadelphia firebombing allegedly ordered by Savage that killed four children and two adults.
About 8:30 p.m. Oct. 8, 2004, in another recorded prison phone call, Savage called the home of his sister, codefendant Kidada Savage. Copeland was in the house at the time and spoke with Savage. As they spoke, Lamont Lewis knocked on the front door, was allowed inside, and spoke with Savage for "maybe a minute or two," Copeland testified.
Lewis admits he firebombed the Coleman family's North Sixth Street home in a predawn attack Oct. 9, 2004, allegedly on order from Savage.
Prosecutors say Savage ordered the firebombing as retaliation against Eugene "Twin" Coleman, a former friend and confidant who had agreed to testify against him.
A woman who lived across the street from the firebombed house, Maggie Jimenez, was called to the stand on Monday by the defense. She said she was at home and awake when the firebombing occurred. She said she heard a man and woman arguing and then heard a window crash. "Within seconds the building was on fire," she said. "I didn't want to look out. I was afraid."
As the defense opened its case, lawyer William Purpurpa pointed out a mistake prosecutors made in the transcript of the June 2006 conversation between Savage and Copeland.
Savage said he would "stick a spy" on Copeland, but the government's transcript said "stick a fire."
Prosecutors agreed to correct the transcript.
Contact Sulaiman Abdur-Rahman at firstname.lastname@example.org, or follow on Twitter @sabdurr.