EXHIBIT 5.1


                       [WILSON SONSINI GOODRICH & ROSATI,
                      PROFESSIONAL CORPORATION LETTERHEAD]


August 1, 2005

ScanSoft, Inc.
9 Centennial Drive
Peabody, Massachusetts 09160

RE: Registration Statement on Form S-4

Ladies and Gentlemen:

     We have examined the Registration Statement on Form S-4 filed by you with
the Securities and Exchange Commission, Registration Number 333-125496 (the
"Registration Statement"), in connection with the registration under the
Securities Act of 1933, as amended, of shares (the "Shares") of your Common
Stock, par value $0.001 per share, and associated preferred share purchase
rights (the "Rights"), to be issued in connection with the merger of Nova
Acquisition Corporation, your wholly-owned subsidiary, with and into Nuance
Communications, Inc., a Delaware corporation, in which Nuance will be the
surviving corporation (the "Interim Surviving Corporation"), and the subsequent
merger of the Interim Surviving Corporation with and into Nova Acquisition LLC,
your wholly-owned subsidiary, as described in the Registration Statement (the
"Transaction"). As your counsel in connection with the Transaction, we have
examined the proceedings taken and are familiar with the proceedings proposed to
be taken by you in connection with the issuance of the Shares in the
Transaction.

     It is our opinion that, when issued in the manner described in the
Registration Statement, the Shares will be legally and validly issued, fully
paid and non-assessable and the Rights attached to the Shares will be legally
and validly issued.

     We consent to the use of this opinion as an exhibit to the Registration
Statement, and further consent to the use of our name whenever appearing in the
Registration Statement and any amendments thereto.

                                        Very truly yours,

                                        /s/ Wilson Sonsini Goodrich & Rosati

                                        Wilson Sonsini Goodrich & Rosati
                                        Professional Corporation