If you can train yourself to do it, it's great to add punctuation with Dragon NaturallySpeaking as you dictate. Here's how to insert common punctuation marks as you speak.

Punctuation Mark Spoken Form
. "Period" (or "Dot," or "Point")
! "Exclamation Mark" (or "Exclamation Point")
? "Question Mark"
, "Comma"
' "Apostrophe"
's "Apostrophe Ess"
& "Ampersand"
: "Colon"
; "Semicolon"
" "Begin Quote"
" "End Quote"
' "Open Single Quote"
' "Close Single Quote"
. . . "Ellipsis"
$ "Dollar Sign"