I believe the answer to be "no". I do not think there is a "more formal or professional verb" that you might use, except possibly to address. Indeed I fail to see what is not formal or professional about speak to used in this way.
It is recognised in the OED as sense 5, of the second meaning of speak meaning to address words or discourse, as opposed to uttering or pronouncing words.
As you will see its first reference is from 1610.
- To treat of or deal with, to discuss or comment on, (a subject) in speech or writing.
1610 J. Dove Advt. Seminaries 42, I desire them therefore..to
speake to these foure points.
1637 P. Heylyn Briefe Answer Burton 78 For your charges,..I meane
to take them..in order, and speake as briefely to them, as you would
1662 E. Stillingfleet Origines Sacræ ii. vi. §4 Though it be a
subject little spoken to either by Jewish or Christian Writers.
1706 G. Stanhope Paraphr. Epist. & Gospels III. 555 Part of this
Scripture hath already been spoken to.
1735 Swift Let. to Middleton in Wks. IV. 186 A Lawyer who speaks
to a Cause, when the Matter hath been almost exhausted by those who
1778 Earl of Malmesbury Diaries & Corr. I. 166 Unprepared as he
was for such a proposition, he could not, he said, off-hand, speak to
1869 Daily News 28 Apr. The report..was spoken to by the Most Rev.
Chairman..and the Bishop of Derry.
1880 Daily News 19 Mar. 2/3, I wish to call your
attention..to..that allegation, and I shall endeavour to speak to it.