You can do it in several ways depending on how you want the slide to look. The easiest may be to use the ppLayoutTitle
instead of ppLayoutTitleOnly
. It has two textframes instead of one, so you could update the text by using something like the following:
slideObject.Shapes(2).TextFrame.TextRange.Text = "This is the subtitle."
If you need a more custom layout, you could add a new textbox by using adding the following at the bottom of your code example:
Set oShp = slideObject.Shapes.AddTextbox(msoTextOrientationHorizontal, 100, 100, 200, 300)
oShp.TextFrame.TextRange.Text = "Row #2: subtitle."
The numeric parameters to the AddTextbox
function set the position and size of the new textbox.
You can update the font the same way for both of the above examples (just change the reference to the textbox):
oShp.TextFrame.TextRange.Font.Bold = msoTrue