Open PPT, press ALT+F11 to open the VBA editor, (for some computers FN+ALT+F11) right-click in the project view on the left, select Insert->Module, add a module, and the name does not need to be changed.
Then click the "Tools" menu at the top, select Reference, find "Microsoft Word X.0 Object Library" (where X is related to your version of OFFICE), hook it, and click OK
Paste the following code into the newly created module and press F5 (FN+F5 on some computers)
Sub Main()
On Error Resume Next
Dim temp As New Word.Document, tmpShape As Shape, tmpSlide As Slide
For Each tmpSlide In ActivePresentation.Slides
For Each tmpShape In tmpSlide.Shapes
temp.Range().Text = temp.Range() + tmpShape.TextFrame.TextRange.Text
Next tmpShape
Next tmpSlide
temp.Application.Visible = True
End Sub