Exhibit 32.1

CERTIFICATION PURSUANT TO

18 U.S.C. SECTION 1350, AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Annual Report of Nuance Communications, Inc. (the “Registrant”) on Form 10-Q for the quarterly period ended March 31, 2005, as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I, Charles W. Berger, Chief Executive Officer of the Registrant, certify, in accordance with 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that to the best of my knowledge:

(1) The Report, to which this certification is attached as Exhibit 32.1, fully complies with the requirements of Sections 13(a) or 15(d) of the Securities Exchange Act of 1934; and

(2) The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Registrant.

A signed original of this written statement required by 18 U.S.C. Section 1350 has been provided to the Registrant and will be retained by the Registrant and furnished to the Securities and Exchange Commission or its staff upon request.

By:	/s/    CHARLES W. BERGER
	Charles W. Berger
	President and Chief Executive Officer
	May 10, 2005