expound

To set out the meaning of; to explain or discuss at length.

Today I'll expound at length the theory propounded last week.

“[…] Some day, when you are tired of London, come down to Treadley, and expound to me your philosophy of pleasure over some admirable Burgundy I am fortunate enough to possess.”

To make a statement, especially at length.

He expounded often on the dangers of the imperial presidency.

Fowler was also interested in metallurgy and the use of new materials that could withstand greater stresses, something he expounded on when giving his presidential address to the new Institution of Mechanical Engineers in 1927.