Re: Converting string to symbol

[excalamus--- via Users list for the GNU Emacs text editor <help-gnu-emacs@gnu.org>]

I got it.  Simply grab the symbol's value once it's been interned.  Thanks again for your help :)
(defun my-add-case-fixed-abbrev (name expansion &optional table)
  "Add fixed case abbrev with NAME and EXPANSION into TABLE.

TABLE is optional; defaults to `global-abbrev-table'."
  (interactive
   (let ((table (symbol-value (intern-soft (completing-read
          "Abbrev table (global-abbrev-table): "
          abbrev-table-name-list nil t nil nil "global-abbrev-table"))))
         (name (read-string "Abbrev name: "))
         (expansion (read-string "Expansion: ")))
     (list name expansion table)))
  (let ((table (or table global-abbrev-table)))
    (define-abbrev table name expansion nil :case-fixed t)))