You can say whatever you want.
You have two issues. Spoken word isn't necessarily protected by copyright. If you had prepared a written version or notes or recorded it yourself, you then establish copyright. Of course without copyright, you or anybody else could do anything anyhow.
The second is what agreement your employment with the university is. It's quite possible they may lay claim to such. Most Universities have an office to deal with such issues.
Third (ok THREE ISSUES) is that if your work was funded at all by a government (or perhaps other) grant, there may be restrictions or at least attribution that maybe required as a condition of that funding.