<PAGE>

                                                                     Exhibit 4.3

THIS SERIES D WARRANT HAS NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933,
AS AMENDED, OR ANY APPLICABLE STATE SECURITIES LAWS, AND MAY NOT BE SOLD OR
TRANSFERRED UNLESS SUCH SALE OR TRANSFER IS IN ACCORDANCE WITH THE REGISTRATION
REQUIREMENTS OF SUCH ACT AND APPLICABLE LAWS OR SOME OTHER EXEMPTION FROM THE
REGISTRATION REQUIREMENTS OF SUCH ACT AND APPLICABLE LAWS IS AVAILABLE WITH
RESPECT THERETO.

              SERIES D CONVERTIBLE PREFERRED STOCK PURCHASE WARRANT

Warrant No. PD-[__]                         Number of Shares: Up to [_______]

                                  VOXWARE, INC.

                         Void after [_______ ___], 2013

     1. Issuance. This Series D Warrant is issued to [_________________] by
Voxware, Inc., a Delaware corporation (hereinafter with its successors called
the "Company").

     2. Purchase Price; Number of Shares. Subject to the terms and conditions
hereinafter set forth, the registered holder of this Series D Warrant (the
"Holder"), commencing on the date hereof, is entitled upon surrender of this
Series D Warrant with the subscription form annexed hereto duly executed, at the
office of the Company, Lawrenceville Office Park, PO Box 5363, Princeton, New
Jersey 08543-5363, or such other office as the Company shall notify the Holder
of in writing, to purchase from the Company at a price per share (the "Purchase
Price") of $0.001, up to [____________] fully paid and nonassessable shares (the
"Maximum Shares") of Series D Convertible Preferred Stock, par value $0.001 per
share, of the Company (the "Series D Preferred Stock"); provided that the actual
number of such shares for which this Series D Warrant shall be exercisable shall
be equal to the number determined by multiplying (i) the result of dividing (A)
the difference between $8,940,000.00 and the Company's "Gross Revenue" for the
fiscal year 2003 (or, if Gross Revenue is not reported for such period, then
such reported measure as is most equivalent under U.S. generally accepted
accounting principals, consistently applied), as reported on an audited basis in
the Company's Annual Report of Form 10-K as filed with the Securities and
Exchange Commission (or if no such report is prepared or filed, as otherwise
determined by the Company and audited by its independent public accountants), by
(B) 840,000, by (ii) the Maximum Shares; provided further, however, that in no
event shall more than the Maximum Shares be issuable pursuant to this Series D
Warrant. Until such time as this Series D Warrant is exercised in full or
expires, the Purchase Price and the securities issuable upon exercise of this
Series D Warrant are subject to adjustment as hereinafter provided.

     3. Payment of Purchase Price. The Purchase Price may be paid (i) in cash or
by check, (ii) by the surrender by the Holder to the Company of any promissory
notes or other obligations issued by the Company, with all such notes and
obligations so surrendered being credited against the Purchase Price in an
amount equal to the principal amount thereof plus accrued interest to the date
of surrender, (iii) through delivery by the Holder to the Company of other
securities issued by the Company, with such

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                                      -2-

securities being credited against the Purchase Price in an amount equal to the
fair market value thereof, as determined in good faith by the Board of Directors
of the Company (the "Board"), or (iv) by any combination of the foregoing. The
Board shall promptly respond in writing to an inquiry by the Holder as to the
fair market value of any securities the Holder may wish to deliver to the
Company pursuant to clause (iii) above.

     4. Net Issue Election. The Holder may elect to receive, without the payment
by the Holder of any additional consideration, shares equal to the value of this
Series D Warrant or any portion hereof by the surrender of this Series D Warrant
or such portion to the Company, with the net issue election notice annexed
hereto duly executed, at the office of the Company. Thereupon, the Company shall
issue to the Holder such number of fully paid and nonassessable shares of Series
D Preferred Stock as is computed using the following formula:

                                   X = Y (A-B)
                                       -------
                                          A

where

          X = the number of shares to be issued to the Holder pursuant to this
          Section 4.

          Y = the number of shares covered by this Series D Warrant in respect
          of which the net issue election is made pursuant to this Section 4.

          A = the fair market value of one share of Series D Preferred Stock, as
          determined in good faith by the Board, as at the time the net issue
          election is made pursuant to this Section 4.

          B = the Purchase Price in effect under this Series D Warrant at the
          time the net issue election is made pursuant to this Section 4.

The Board shall promptly respond in writing to an inquiry by the Holder as to
the fair market value of one share of Series D Preferred Stock.

     5. Partial Exercise. This Series D Warrant may be exercised in part, and
the Holder shall be entitled to receive a new warrant, which shall be dated as
of the date of this Series D Warrant, covering the number of shares in respect
of which this Series D Warrant shall not have been exercised.

     6. Issuance Date. The person or persons in whose name or names any
certificate representing shares of Series D Preferred Stock is issued hereunder
shall be deemed to have become the holder of record of the shares represented
thereby as at the close of business on the date this Series D Warrant is
exercised with respect to such shares, whether or not the transfer books of the
Company shall be closed.

     7. Expiration Date; Automatic Exercise. This Series D Warrant shall expire
at the close of business on [_______ ___]    , 2013, and shall be void
                                          ---
thereafter. Notwithstanding the foregoing, this Series D Warrant, to the extent
then exercisable, shall automatically be deemed to be exercised in full pursuant
to the provisions of Section 4 hereof, without any further action on behalf of
the Holder, immediately prior to the time this Series D Warrant would otherwise
expire pursuant to the preceding sentence.

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                                      -3-

     8. Reserved Shares; Valid Issuance. The Company covenants that it will at
all times from and after the date hereof reserve and keep available such number
of its authorized shares of Series D Preferred Stock and Common Stock, par value
$0.001 per share (the "Common Stock"), free from all preemptive or similar
rights therein, as will be sufficient to permit, respectively, the exercise of
this Series D Warrant in full and the conversion into shares of Common Stock of
all shares of Series D Preferred Stock receivable upon such exercise. The
Company further covenants that such shares as may be issued pursuant to such
exercise and conversion will, upon issuance, be duly and validly issued, fully
paid and nonassessable and free from all taxes, liens and charges with respect
to the issuance thereof.

     9. Stock Dividends. If after the Original Issue Date (as defined in Section
14 hereof) the Company shall subdivide the Series D Preferred Stock, by split-up
or otherwise, or combine the Series D Preferred Stock, or issue additional
shares of Series D Preferred Stock in payment of a stock dividend on the Series
D Preferred Stock, the number of shares issuable on the exercise of this Series
D Warrant shall forthwith be proportionately increased in the case of a
subdivision or stock dividend, or proportionately decreased in the case of a
combination, and the Purchase Price shall forthwith be proportionately decreased
in the case of a subdivision or stock dividend, or proportionately increased in
the case of a combination.

     10. Mergers and Reclassifications. If after the Original Issue Date there
shall be any reclassification, capital reorganization or change of the Series D
Preferred Stock (other than as a result of a subdivision, combination or stock
dividend provided for in Section 9 hereof), or any consolidation of the Company
with, or merger of the Company into, another corporation or other business
organization (other than a consolidation or merger in which the Company is the
continuing corporation and which does not result in any reclassification or
change of the outstanding Series D Preferred Stock), or any sale or conveyance
to another corporation or other business organization of all or substantially
all of the assets of the Company, then, as a condition of such reclassification,
reorganization, change, consolidation, merger, sale or conveyance, lawful
provisions shall be made, and duly executed documents evidencing the same from
the Company or its successor shall be delivered to the Holder, so that the
Holder shall thereafter have the right to purchase, at a total price not to
exceed that payable upon the exercise of this Series D Warrant in full, the kind
and amount of shares of stock and other securities and property receivable upon
such reclassification, reorganization, change, consolidation, merger, sale or
conveyance by a holder of the number of shares of Series D Preferred Stock which
might have been purchased by the Holder immediately prior to such
reclassification, reorganization, change, consolidation, merger, sale or
conveyance (or, if there are no holders of Series D Preferred Stock at such
time, by a holder of the number of shares of Common Stock which might have been
acquired by the Holder immediately prior to such reclassification,
reorganization, change, consolidation, merger, sale or conveyance upon the
exercise of this Series D Warrant in full and the conversion into shares of
Common Stock of all shares of Series D Preferred Stock receivable upon such
exercise), and in any such case appropriate provisions shall be made with
respect to the rights and interest of the Holder to the end that the provisions
hereof (including without limitation, provisions for the adjustment of the
Purchase Price and the number of shares issuable hereunder) shall thereafter be
applicable in relation to any shares of stock or other securities and property
thereafter deliverable upon exercise hereof.

     11. Fractional Shares. In no event shall any fractional share of Series D
Preferred Stock be issued upon any exercise of this Series D Warrant. If, upon
exercise of this Series D Warrant as an entirety, the Holder would, except as
provided in this Section 11, be entitled to receive a fractional share of Series
D Preferred Stock, then the Company shall issue the next higher number of full
shares of Series D Preferred Stock, issuing a full share with respect to such
fractional share.

     12. Certificate of Adjustment. Whenever the Purchase Price is adjusted, as
herein provided, the Company shall promptly deliver to the Holder a certificate
of a firm of independent public

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                                      -4-

accountants setting forth the Purchase Price after such adjustment and setting
forth a brief statement of the facts requiring such adjustment.

     13. Notices of Record Date, Etc. In the event of:

          (a) any taking by the Company of a record of the holders of any class
of securities for the purpose of determining the holders thereof who are
entitled to receive any dividend or other distribution, or any right to
subscribe for, purchase or otherwise acquire any shares of stock of any class or
any other securities or property, or to receive any other right,

          (b) any reclassification of the capital stock of the Company, capital
reorganization of the Company, consolidation or merger involving the Company, or
sale or conveyance of all or substantially all of its assets, or

          (c) any voluntary or involuntary dissolution, liquidation or
winding-up of the Company,

then and in each such event the Company will mail or cause to be mailed to the
Holder a notice specifying (i) the date on which any such record is to be taken
for the purpose of such dividend, distribution or right, and stating the amount
and character of such dividend, distribution or right, or (ii) the date on which
any such reclassification, reorganization, consolidation, merger, sale or
conveyance, dissolution, liquidation or winding-up is to take place, and the
time, if any is to be fixed, as of which the holders of record in respect of
such event are to be determined. Such notice shall be mailed at least 20 days
prior to the date specified in such notice on which any such action is to be
taken.

     14. Other Series D Warrants. This Series D Warrant is one of a series of
warrants for Series D Preferred Stock (collectively, the "Series D Warrants")
that were originally issued by the Company on [_______ ___]    , 2003 (the
                                                            ---
"Original Issue Date") pursuant to a Series D Convertible Preferred Stock
Purchase Agreement, dated April 16, 2003, by and among the Company and the other
parties thereto.

     15. Amendment. The terms of this Series D Warrant may be amended, modified
or waived only with the written consent of the Company and the holders of Series
D Warrants representing at least a majority of the number of shares of Series D
Preferred Stock then issuable upon the exercise of the Series D Warrants. No
such amendment, modification or waiver shall be effective as to this Series D
Warrant unless the terms of such amendment, modification or waiver shall apply
with the same force and effect to all of the other Series D Warrants then
outstanding.

     16. Series D Warrant Register; Transfers, Etc.

          A. The Company will maintain a register containing the names and
addresses of the registered holders of the Series D Warrants. The Holder may
change its address as shown on the warrant register by written notice to the
Company requesting such change. Any notice or written communication required or
permitted to be given to the Holder may be given by certified mail or delivered
to the Holder at its address as shown on the warrant register.

          B. Subject to compliance with applicable federal and state securities
laws, this Series D Warrant may be transferred by the Holder with respect to any
or all of the shares purchasable hereunder. Upon surrender of this Series D
Warrant to the Company, together with the assignment hereof properly endorsed,
for transfer of this Series D Warrant as an entirety by the Holder, the Company
shall issue a new warrant of the same denomination to the assignee. Upon
surrender of this Series D Warrant to the Company, together with the assignment
hereof properly endorsed, by the Holder for

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                                      -5-

transfer with respect to a portion of the shares of Series D Preferred Stock
purchasable hereunder, the Company shall issue a new warrant to the assignee, in
such denomination as shall be requested by the Holder hereof, and shall issue to
such Holder a new warrant covering the number of shares in respect of which this
Series D Warrant shall not have been transferred.

          C. In case this Series D Warrant shall be mutilated, lost, stolen or
destroyed, the Company shall issue a new warrant of like tenor and denomination
and deliver the same (i) in exchange and substitution for and upon surrender and
cancellation of any mutilated Series D Warrant, or (ii) in lieu of any Series D
Warrant lost, stolen or destroyed, upon receipt of evidence reasonably
satisfactory to the Company of the loss, theft or destruction of such Series D
Warrant (including a reasonably detailed affidavit with respect to the
circumstances of any loss, theft or destruction) and of indemnity reasonably
satisfactory to the Company, provided, however, that so long as [_____________]
is the registered holder of this Series D Warrant, no indemnity shall be
required other than its written agreement to indemnify the Company against any
loss arising from the issuance of such new warrant.

     17. No Impairment. The Company will not, by amendment of its Amended and
Restated Certificate of Incorporation or through any reclassification, capital
reorganization, consolidation, merger, sale or conveyance of assets,
dissolution, liquidation, issue or sale of securities or any other voluntary
action, avoid or seek to avoid the observance or performance of any of the terms
of this Series D Warrant, but will at all times in good faith assist in the
carrying out of all such terms and in the taking of all such action as may be
necessary or appropriate in order to protect the rights of the Holder.

     18. Governing Law. The provisions and terms of this Series D Warrant shall
be construed and enforced in accordance with and governed by the laws of the
General Corporation Law of the State of Delaware as to matters within the scope
thereof, and as to all other matters shall be construed and enforced in
accordance with and governed by the internal laws of the State of New Jersey,
without regard to its principles of conflicts of laws.

     19. Successors and Assigns. This Series D Warrant shall be binding upon the
Company's successors and assigns and shall inure to the benefit of the Holder's
successors, legal representatives and permitted assigns.

     20. Business Days. If the last or appointed day for the taking of any
action required or the expiration of any right granted herein shall be a
Saturday or Sunday or a legal holiday in the State of New Jersey, then such
action may be taken or right may be exercised on the next succeeding day which
is not a Saturday or Sunday or such a legal holiday.

Dated: [_______ ___]    , 2003         VOXWARE, INC.
                     ---


(Corporate Seal)                       By:
                                          --------------------------------------

Attest:                                Title:
                                             -----------------------------------

-----------------------------

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                                      -6-

                                  Subscription

To:                                    Date:
   --------------------                     -------------------------

     The undersigned hereby subscribes for            shares of Series D
                                           ----------
Preferred Stock covered by this Series D Warrant. The certificate(s) for such
shares shall be issued in the name of the undersigned or as otherwise indicated
below:


                                       -----------------------------------------
                                       Signature

                                       -----------------------------------------
                                       Name for Registration

                                       -----------------------------------------
                                       Mailing Address

                            Net Issue Election Notice

To:                                      Date:
   --------------------                       -------------------------

     The undersigned hereby elects under Section 4 to surrender the right to
purchase                shares of Series D Preferred Stock pursuant to this
         --------------
Series D Warrant. The certificate(s) for the shares issuable upon such net issue
election shall be issued in the name of the undersigned or as otherwise
indicated below.


                                       -----------------------------------------
                                       Signature

                                       -----------------------------------------
                                       Name for Registration

                                       -----------------------------------------
                                       Mailing Address

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                                      -7-

                                   Assignment

     For value received, the undersigned hereby sells, assigns and transfers
unto                             ,/1/ the right represented by the within Series
     ----------------------------
D Warrant to purchase            shares of Series D Preferred Stock of Voxware,
                      ----------
Inc. (the "Company") to which the within Series D Warrant relates, and does
hereby irrevocably constitute and appoint the Company as its attorney to
transfer such right to the within Series D Warrant on the books of the Company
with full power of substitution on the premises.

Dated:
      -----------------------


                                       Signature:
                                                  ------------------------------

                                       Assignor Name:
                                                      --------------------------


                                                By:
                                                Its:
                                       (Name must conform to name of Holder as
                                       specified on the face of the Series D
                                       Warrant)

In the Presence of:


-----------------------------

Assignee Information

Name:
      ------------------------------

Address:
         ---------------------------

         ---------------------------
Telephone:
           -------------------------

Facsimile:
           -------------------------

----------
/1/  (full name of assignee)