It was an emotional Wednesday in Brooklyn Supreme Court as 18-year-old Tammy Lewis took the stand to testify against Shaquan Taylor, who's charged with assaulting their 16-month-old daughter on Father's Day 2017.

Taylor is also accused of attacking Lewis when she tried to get help for the child, named Nylah.

The testimony was unbearable at times for the family, who walked out of the courtroom after seeing video of Taylor punching Lewis.

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Lewis testified that on the Friday of Father's Day weekend, she dropped Nylah at Taylor's Coney Island home because she says he asked to see the baby for that weekend. On Father's Day, she says she received Facebook messages from Taylor saying the little girl was throwing up and that Lewis needed to immediately pick up the baby.

Lewis says when she got there, Taylor was sweating and pointed to the baby lying on the couch. She says Nylah was on her back, face up, and was not responding.

Prosecutors say Nylah suffered skull fractures that were intentionally inflicted by Taylor. He's charged with assault, endangering the welfare of a child and harassment, among other charges.

Taylor maintains that his daughter fell off the bed while he was in the shower.