<PAGE>

                                                                     Exhibit 4.2

THE SALE, PLEDGE, HYPOTHECATION, ASSIGNMENT OR TRANSFER OF THE WARRANTS
REPRESENTED BY THIS CERTIFICATE AND THE SHARES OF COMMON STOCK WHICH MAY BE
ACQUIRED UPON THE EXERCISE HEREOF ARE SUBJECT TO THE TERMS AND CONDITIONS OF A
CERTAIN STOCK RESTRICTION AND REGISTRATION RIGHTS AGREEMENT DATED APRIL 4, 2000,
MADE BY THE HOLDER, INROAD, INC., THE COMPANY AND THE WHOLLY-OWNED SUBSIDIARY OF
THE COMPANY (THE "RIGHTS AGREEMENT"). COPIES OF SUCH AGREEMENT MAY BE OBTAINED
UPON WRITTEN REQUEST TO THE SECRETARY OF THE COMPANY.

THE WARRANTS REPRESENTED BY THIS CERTIFICATE AND THE SHARES OF COMMON STOCK
WHICH MAY BE ACQUIRED UPON THE EXERCISE HEREOF HAVE NOT BEEN REGISTERED UNDER
THE SECURITIES ACT OF 1933, AS AMENDED, AND MAY NOT BE SOLD, TRANSFERRED,
PLEDGED OR HYPOTHE CATED IN THE ABSENCE OF AN EFFECTIVE REGISTRATION STATEMENT
FOR SUCH WARRANTS OR SHARES UNDER THE SECURITIES ACT OF 1933, AS AMENDED, OR ANY
APPLICABLE STATE SECURITIES LAWS OR AN APPLICABLE EXEMPTION FROM SUCH
REGISTRATION.



Warrant No. S-1             Right to purchase up to 50,000 Shares of Common
                            Stock (subject to adjustment as described herein) of
                            Voxware, Inc.



                                  VOXWARE, INC.

                               WARRANT CERTIFICATE

                              Issued April 4, 2000

           Exercisable on or before 5:00 P.M., New York April 4, 2005

     1. Grant. THIS WARRANT CERTIFICATE CERTIFIES THAT for value received,
STRATOS PRODUCT DEVELOPMENT, LLC is the registered holder ("Holder") of Fifty
Thousand (50,000) warrants (each a "Warrant" and collectively "Warrants") to
purchase at any time from the date hereof until, subject to Section 3 hereof,
5:00 P.M. New York time on April 4, 2005 (the "Expiration Date"), up to a total
of Fifty Thousand (50,000) fully paid and non-assessable shares (each a "Share"
and collectively "Shares"), of common stock, par value $.001 per share ("Common
Stock") of VOXWARE, INC., a Delaware corporation (the "Company"), at the
Exercise Price (as defined in Section 2 below), upon surrender of this Warrant
Certificate and payment of the Exercise Price at the offices or agency of the
Company, but subject to the conditions set forth herein. Payment of the Exercise
Price shall be made by check or money order payable to the order of the
<PAGE>

Company. No Warrant may be exercised after 5:00 P.M. New York time, on the
Expiration Date, at which time all Warrants evidenced hereby, unless exercised
prior thereto, shall become void. Neither this Warrant Certificate (nor any
replacement Warrant Certificate) nor any rights of the Holder hereof may be
transferred or assigned without the prior written consent of the Company, which
consent may be given or withheld in the sole discretion of the Company.

     The Warrants evidenced by this Warrant Certificate are a duly authorized
issue of warrants issued pursuant to that certain Release Agreement, dated April
4, 2000, by and among the Company, InRoad, Inc., a Delaware corporation, and
Holder.

     2. Exercise Price. The exercise price of the Warrants shall be $3.08 per
share of Common Stock, subject to adjustment as set forth herein.

     3. Exercise of Warrant. Subject to the terms and conditions hereof, the
Warrants are exercisable in whole or in part, on one or more occasions, upon
payment of the Exercise Price for the shares being purchased, payable to the
Company by certified check or money order. Upon surrender of a Warrant
Certificate with the annexed Form of Election to Purchase duly executed,
together with payment of the Exercise Price for the Shares purchased at the
Company's principal offices at 305 College Road East, Princeton, New Jersey
08540 (or such other place as may be the Company's principal offices from time
to time) and subject to satisfaction of the terms and conditions hereof, the
Holder hereof shall be entitled to receive a certificate or certificates for the
Shares so purchased. The rights represented hereby are exercisable at the option
of the Holder hereof, in whole or in part (but not as to fractional Shares),
subject to the terms of this Warrant Certificate. In the case of the purchase of
less than all the Shares purchasable hereunder the Company shall cancel this
Warrant Certificate upon the surrender hereof and shall execute and deliver a
new Warrant Certificate of like tenor for the balance of the Shares purchasable
hereunder. The Company may deem and treat the registered holder(s) hereof as the
absolute owner(s) of this Warrant Certificate (notwithstanding any notation of
ownership or other writing hereon made by anyone), for the purpose of any
exercise hereof, and of any distribution to the holder(s) hereof, and for all
other purposes, and the Company shall not be affected by any notice to the
contrary.

     4. Issuance of Certificates. (a) Upon the exercise of the Warrants in
accordance with the provisions hereof, certificates for Shares issuable upon
exercise of the Warrants shall be issued forthwith and in any event within seven
business days thereafter. The Holder exercising this Warrant shall be deemed for
all purposes to become the legal holder of the Shares issuable upon such
exercise when all conditions to exercise (as specified in Section 3 above) are
satisfied, without regard to any delay thereafter in the issuance and delivery
of the certificates representing such Shares.

        (b) Certificates for the Shares will be issued without charge
(including, without limitation, any tax which may be payable in respect of the
issuance thereof) to the Holder(s) hereof and such certificates shall be issued
in the name of, or in such names as may be directed by, the Holder hereof. The
Company shall not be required to pay any tax which may be payable in respect of
any transfer of any Warrants involved in the issuance and delivery of any such
certificates in the name other than that of the Holder and the Company shall not
be required to issue or deliver such certificates unless or until the person or
persons requesting the issuance thereof shall have paid to the

                                      -2-
<PAGE>

Company the amount of such tax or shall have established to the satisfaction of
the Company that such tax has been paid.

     5. Adjustments of Number of Shares. The number of Shares purchasable upon
exercise of each Warrant shall be subject to adjustment from time-to-time as
follows:

        5.1 Subdivisions, Combinations and Other Issuances. If the Company shall
at any time prior to the expiration of this Warrant subdivide its Common Stock,
by split-up or otherwise, or combine its Common Stock, or issue additional
shares of its Common Stock as a dividend with respect to any shares of its
Common Stock, the number of Shares issuable on the exercise of this Warrant
shall forthwith be proportionately increased in the case of a subdivision or
stock dividend, or proportionately decreased in the case of a combination.
Appropriate adjustments shall also be made to the purchase price payable per
Share, but the aggregate purchase price payable for the total number of Shares
purchasable under this Warrant (as adjusted) shall remain the same. Any
adjustment under this Section 5.1 shall become effective at the close of
business on the date the subdivision or combination becomes effective, or as of
the record date of such dividend, or in the event that no record date is fixed,
upon the making of such dividend.

        5.2 Reclassification, Reorganization and Consolidation. In case of any
reclassification, capital reorganization, or change in the Common Stock of the
Company (other than as a result of a subdivision, combination, or stock dividend
provided for in Section 5.1 above), then lawful provision shall be made so that
the Holder shall have the right at any time prior to the expiration of this
Warrant to purchase, at a total price equal to that payable upon the exercise of
this Warrant, the kind and amount of shares of stock and other securities and
property receivable in connection with such reclassification, reorganization, or
change by a holder of the same number of shares of Common Stock as were
purchasable by the Holder immediately prior to such reclassification,
reorganization, or change. In any such case appropriate provisions shall be made
with respect to the rights and interest of the Holder so that the provisions
hereof shall thereafter be applicable with respect to any shares of stock or
other securities and property deliverable upon exercise hereof, and appropriate
adjustments shall be made to the purchase price per share payable hereunder,
provided the aggregate purchase price shall remain the same.

        5.3 Merger or Consolidation. In the case of a merger, consolidation or
similar transaction which results in a replacement of the Company's Common Stock
with the stock of another corporation, the Company will make a reasonable
effort, but shall not be required, to replace this Warrant, to the extent it has
not been previously exercised, with a comparable warrant to purchase the stock
of such other corporation. To the extent this Warrant is not replaced and is not
exercised prior to the closing of the merger, consolidation or other
transaction, this Warrant shall be terminated (provided the Holder has been
given advance notice pursuant to Section 5.4 below). Notwithstanding the
foregoing, if the Company is the surviving corporation in the merger and the
holders of the Common Stock of the Company hold at least a majority of the
voting power of the surviving corporation after the merger, the Company shall be
obligated to replace this Warrant with a comparable warrant to purchase the
stock of the surviving corporation.

        5.4 Notice of Adjustment. Whenever there shall be an adjustment pursuant
to this Section 5, or a transaction or proposed transaction that would result in
an adjustment pursuant to

                                      -3-
<PAGE>

this Section 5, the Company shall cause written notice thereof to be sent to the
Holder of the Warrants, accompanied by a certificate, signed by an officer of
the Company, setting forth (i) a brief statement of the facts requiring such
adjustment or a brief description of the transaction that would require such
adjustment, (ii) the number of shares of Common Stock or other securities
purchasable upon the exercise hereof after giving effect to such adjustment, and
(iii) the method by which the adjustment was calculated. Such written notice
shall be given at least fifteen (15) days in advance of (a) any record date for
determining shareholders entitled to receive notice of and to vote with respect
to any proposed transaction or other adjustment event, and (b) the effective
date of any proposed transaction or other adjustment event.

        5.5 No Change in Purchase Price; No Change of Warrant. Unless otherwise
indicated, none of the events specified in this Section 5 shall give rise to an
adjustment in the purchase price specified in the opening paragraph herein. The
form of this Warrant Certificate need not be changed because of any adjustment
in number and kind of shares of Common Stock purchasable hereunder pursuant to
this Section 5. Any Warrant issued after any such adjustment upon any partial
exercise or upon replacement or transfer may continue to express the same terms
as are stated in this Warrant Certificate as initially issued, and the number
and kind of shares of Common Stock purchasable hereunder shall be considered to
have been so changed as to the close of business on the date or dates of
adjustment.

     6. Replacement of Warrant Certificate. Upon receipt of evidence reasonably
satisfactory to the Company of the loss, theft, destruction or mutilation of
this Warrant Certificate and, in the case of any such loss, theft or destruction
of any Warrant Certificate, upon delivery of a contractual agreement of
indemnity reasonably satisfactory to the Company, or, in the case of any such
mutilation, upon surrender and cancellation of this Warrant Certificate at the
principal office of the Company, the Company at its expense will execute and
deliver, in lieu thereof, a new Warrant Certificate of like tenor.

     7. Elimination of Fractional Interests. The Company shall not be required
to issue certificates representing fractions of shares of Common Stock on the
exercise of the Warrants, nor shall it be required to pay cash in lieu of
fractional interests, it being the intent of all the parties that all fractional
interests shall be eliminated by rounding any fraction equal to or greater than
one-half up to the nearest whole number of shares of Common Stock and by
rounding any fraction less than one-half down to the nearest whole number of
shares of Common Stock.

     8. Reservation of Common Stock. The Company shall at all times reserve and
keep available out of its authorized shares of Common Stock, solely for the
purpose of issuance upon the exercise of the Warrants such number of shares of
Common Stock as shall be issuable upon the exercise thereof. The Company
covenants and agrees that, upon exercise of the Warrants and payment of the
Exercise Price therefor, all Shares of Common Stock issuable upon such exercise
shall be duly and validly issued, fully paid and non-assessable.

     9. No Rights as Stockholder. Except as specified in Section 5.4 above,
nothing contained in this Warrant shall be construed as conferring upon the
Holder the right to vote or to consent or to receive notice as a stockholder in
respect of any meetings of stockholders for the election of directors or any
other matter, or as having any rights whatsoever as a stockholder of the

                                      -4-
<PAGE>

Company; provided, that the Holder shall be entitled to such rights immediately
upon satisfaction of all conditions to exercise of this Warrant (as specified in
Section 3 above).

     10. Transferability; Successors. Neither this Warrant nor any rights of the
Holder hereof may be transferred or assigned, in whole or in part, except with
the prior written consent of the Company. Subject to the foregoing, the terms
and provisions of this Warrant shall inure to the benefit of, and be binding
upon, the Company and the Holder hereof and their respective successors and
assigns.

     11. Amendments and Waivers. Any term of this Warrant may be amended and the
observance of any term of this Warrant may be waived (either generally or in a
particular instance and either retroactively or prospectively), with the written
consent of the Company and the Holder.

     12. Notices. All notices required or permitted hereunder shall be in
writing and shall be sufficiently given if: (a) hand delivered (in which case
the notice shall be effective upon delivery); (b) telecopied, provided that in
                                                              --------
such case a copy of such notice shall be concurrently sent by registered or
certified mail, return receipt requested, postage prepaid (in which case the
notice shall be effective two days following dispatch); (c) delivered by Express
Mail, Fed Ex or other nationally recognized overnight courier service (in which
case the notice shall be effective one business day following dispatch); or (d)
delivered or mailed by registered or certified mail, return receipt requested,
postage prepaid (in which case the notice shall be effective three days
following dispatch), to the parties at the following addresses and/or telecopier
numbers, or to such other address or number as a party shall specify by written
notice to the others.

     If to the Holder:
     -----------------
Stratos Product Development, LLC 2025 First Avenue Market Place Tower PHB
Seattle, Washington 98121 Attention: Mr. Al Stephan

     If to the Company:
     ------------------
Voxware, Inc. 305 College Road East Princeton, New Jersey 08540 Attention: Mr.
Nicholas Narlis

     13. Termination. The rights and benefits evidenced by this Warrant
Certificate shall terminate and expire at 5:00 p.m. New York time on April 4,
2005 or on any earlier date when all Warrants have been exercised.

     14. Governing Law. This Warrant Certificate shall be deemed to be a
contract made under the laws of the State of New York and for all purposes shall
be construed in accordance with its laws without giving effect to the rules
governing the conflicts of laws.

     15. Headings. The Article and Section headings in this Warrant Certificate
are inserted for purposes of convenience only and shall have no substantive
effect.

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<PAGE>

     IN WITNESS WHEREOF, Voxware has caused this Warrant to be duly executed as
of the day and year first above written.

                                       VOXWARE, INC.


                                       By: /s/ Bathsheba J. Malsheen
                                           -------------------------------------
                                           Bathsheba Malsheen, President


                                       By: /s/ Nicholas Narlis
                                           -------------------------------------
                                           Nicholas Narlis, Secretary

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