Ashiqur Rahman, 25, has pleaded not guilty to manslaughter and aggravated assault in the July 2009 death of seven-week-old Aurora Breakthrough.
Lawyer Donald Murray told Judge Felix Cacchione of the Supreme Court of Nova Scotia on Monday that his client has chosen to testify.
"I think he (Rahman) will be able to make a good contribution to the evidence available to the judge," Murray said outside court.
The Crown introduced two emails on Monday that Rahman sent to Aurora's mother, Jane Gomes, about a technology business he created in January 2009.
At the time they had left their computer science studies at Acadia University in Wolfville, N.S., and had moved into a small apartment in Halifax.
In the email, Rahman offered Gomes a job for a product he created called Maxwind. He signed the email, dated Jan. 8, 2009, as the chairman and chief executive of Lastfuture Inc.
Two weeks later, he sent another email to Gomes that said: "I am not hiring you now considering your current competence."
Gomes said she didn't know what she was doing incorrectly or why her partner had decided against hiring her.
Outside court, Crown attorney Denise Smith said the emails help give the judge a sense of the relationship between the couple.
Gomes was recalled to testify Monday after court heard that police hadn't disclosed the email evidence to the Crown earlier in the trial. Smith said the material wasn't disclosed to the Crown because of technical and human error.
Murray didn't ask any questions about the emails, but he did cross-examine Gomes about an email she sent to her sister criticizing her aunt and grandfather in the fall of 2008 after her grandfather complained about her falling grades.
Gomes testified that she had made angry remarks in the email because she was frustrated that her aunt had hung up on her during a telephone conversation.
Gomes pleaded guilty last year to failing to provide the necessities of life and received a conditional discharge with six months of probation.
Court has heard that the medical examiner's autopsy concluded Aurora died due to "non-accidental trauma."
Gomes has testified that she saw Rahman slap and shake Aurora on two occasions in the weeks before her death.
Rahman is scheduled to begin his testimony on Jan. 3.