<PAGE>   1
                                                                     Exhibit 3.3

                                                          FEDERAL IDENTIFICATION
                                                          NO. 04-2814792
                                                              ------------------
   BT
--------               THE COMMONWEALTH OF MASSACHUSETTS
Examiner                     WILLIAM FRANCIS GALVIN
                         Secretary of the Commonwealth
  N/A        One Ashburton Place, Boston, Massachusetts 02108-1512
--------
Name                          ARTICLES OF AMENDMENT
Approved            (General Laws, Chapter 156B, Section 72)


          We, Eric R. Giler                                         , *President
              ------------------------------------------------------

          and David W. Duehren                                          , *Clerk
              ----------------------------------------------------------

          of Brooktrout, Inc.                                                  ,
             ------------------------------------------------------------------
                               (Exact name of corporation)

          located at 410 First Avenue, Needham, MA  02494                      ,
                     ----------------------------------------------------------
                          (Street address of corporation in Massachusetts)

          certify that these Articles of Amendment affecting articles numbered:

          Three
          ----------------------------------------------------------------------
               (Number those articles 1, 2, 3, 4, 5 and/or 6 being amended)

          of the Articles of Organization were duly adopted at a meeting held on
          May 11, 2000 by vote of:
          ------------

          9,498,257 shares of Common Stock, $.01 par value of 12,159,580 shares
          ---------           ----------------------------    ----------
                                                                   outstanding,
                             (type, class & series, if any)


          _________ shares of _____________ of _________ shares outstanding, and
                        (type, class & series, if any)

          _________ shares of _________________ of _________ shares outstanding,
                        (type, class & series, if any)

C    [ ]
P    [ ]  (1)**being at least a majority of each type, class or series
M    [ ]  outstanding and entitled to vote thereon:/or (2)**being at least two-
R.A. [ ]  thirds of each type, class or series outstanding and entitled to vote
          thereon and of each type, class or series of stock whose rights are
          adversely affected thereby:

          *Delete the inapplicable words.      **Delete the inapplicable clause.
   3      (1) For amendments adopted pursuant to Chapter 156B, Section 70.
-------   (2) For amendments adopted pursuant to Chapter 156B, Section 71.
 .C.       Note: If the space provided under any article or item on this form is
          insufficient, additions shall be set forth on one side only of
          separate 8 1/2 x 11 sheets of paper with a left margin of at least 1
          inch. Additions to more than one article may be made on a single sheet
          so long as each article requiring each addition is clearly indicated.


<PAGE>   2


To change the number of shares and the par value (if any) of any type, class or
series of stock which the corporation is authorized to issue, fill in the
following:

The total presently authorized is:

<TABLE>
<CAPTION>
--------------------------------------------------------------------------------
        WITHOUT PAR VALUE STOCKS              WITH PAR VALUE STOCKS
--------------------------------------------------------------------------------
  TYPE      NUMBER OF SHARES      TYPE           NUMBER OF SHARES      PAR VALUE
--------------------------------------------------------------------------------
<S>         <C>                 <C>              <C>                   <C>
Common:             --          Common:             25,000,000          $    .01
--------------------------------------------------------------------------------

--------------------------------------------------------------------------------
Preferred:          --          Preferred:             100,000          $   1.00
--------------------------------------------------------------------------------

--------------------------------------------------------------------------------
</TABLE>

Change the total authorized to:

<TABLE>
<CAPTION>
--------------------------------------------------------------------------------
        WITHOUT PAR VALUE STOCKS              WITH PAR VALUE STOCKS
--------------------------------------------------------------------------------
  TYPE      NUMBER OF SHARES      TYPE           NUMBER OF SHARES      PAR VALUE
--------------------------------------------------------------------------------
<S>         <C>                 <C>              <C>                   <C>
Common:             --          Common:             40,000,000          $    .01
--------------------------------------------------------------------------------

--------------------------------------------------------------------------------
Preferred:          --          Preferred:             100,000          $   1.00
--------------------------------------------------------------------------------

--------------------------------------------------------------------------------
</TABLE>


<PAGE>   3


                                     705633

                       THE COMMONWEALTH OF MASSACHUSETTS
                                                                         #949113

                             ARTICLES OF AMENDMENT
                    (GENERAL LAWS, CHAPTER 156B, SECTION 72)

================================================================================

I hereby approve the within Articles of Amendment and, the filing fee in the
amount of $15,000 having been paid, said articles are deemed to have been filed
with me this 11th day of May 2000.


Effective Date: ________________________________________________________________


                           /s/ William Francis Galvin

                             WILLIAM FRANCIS GALVIN
                         Secretary of the Commonwealth
                                                                SECRETARY OF
                                                              THE COMMONWEALTH

                                                             00 MAY 11  PM 2:11

                         TO BE FILLED IN BY CORPORATION
                      PHOTOCOPY OF DOCUMENT TO BE SENT TO:

                               Danielle Gosselin
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                               Goodwin, Procter & Hoar LLP
                               Exchange Place
--------------------------------------------------------------------------------
                               53 State Street
                               Boston, MA 02109
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Telephone:                          570-1000
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