A judge sentenced a South Philadelphia man to 20 to 40 years in prison Friday for raping his girlfriend's daughter, a 16-year-old who has severe cerebral palsy.

Charles Finch, 44, was found guilty in May, after a two-week trial during which his victim testified. The Inquirer does not name victims of sexual assault.

Prosecutors praised the victim's courage in coming forward to report the 2009 attack. The girl, who has had cerebral palsy since birth, uses a wheelchair and has difficulty communicating, but told her mother of the rape and made numerous court appearances in the case, testifying for hours with help from an interpreter.

"[Finch] picked someone he thought was a voiceless, weak victim who he thought would never be able to speak of what happened," Assistant District Attorney Jim Carpenter told Common Pleas Court Judge Genece E. Brinkley on Friday. "Well, he was wrong. He picked the wrong girl."

Mythri Jayaraman, Finch's defense attorney, asked that Finch be sentenced to six to 12 years, citing his strong family network and a record that includes no history of sexual assault. She said Finch came from a good family, had 13 children he was trying to support, and was engaged to a woman who is eight months pregnant.

Given the chance to address Brinkley, Finch maintained that he did not commit the rape.

"I'm well-loved out there in the streets," he said. "I'm innocent, Your Honor."

Carpenter noted that Finch had been in and out of jail for years on charges of burglary, theft, and assault, tested positive for cocaine use this year, and had not always paid child support.

In fact, prosecutors said Finch committed the rape just two days after he was released from jail in January 2009. He went to stay with his girlfriend at the time, the teenage victim's mother, in their apartment on Addison Street in South Philadelphia. His second night there, he crept into the girl's bedroom, prosecutors said.

The girl later told her mother, then used a touch-screen device to report the crime to police. By the time the case went to trial, her manual dexterity had deteriorated, and she testified with help from an expert who was familiar with her speech patterns - a type of interpreter authorities said they believed had never been used in a Philadelphia trial.

The rape and resulting court proceedings were traumatic for the victim, said Assistant District Attorney Jack O'Neill, who prosecuted the case.

"She was a good student and a kid who was known for cheering everyone else up when they were down," he said. "She sank into a yearlong depression."

The girl, now 18, was glad to hear of the sentence, he said. She is taking college courses.

Brinkley said Finch's history and his denial of responsibility for the rape were factors in her decision to sentence him to more time than the guidelines called for.

Almost a dozen of Finch's relatives attended the hearing, as did his pregnant fiancée, who wiped tears from her eyes as he was taken away.

Contact Allison Steele at 215-854-2641 or asteele@phillynews.com.