<PAGE>
Filed Pursuant to Rule 424(b)(3) and (c)
File Number 333-74603
PROSPECTUS SUPPLEMENT DATED JANUARY 11, 2000
to
Prospectus dated March 31, 1999
490,000,000
Aspect Communications Corporation
Zero Coupon Convertible Subordinated Debentures and
Shares of Common Stock Issuable Upon Conversion of the Debentures
This Prospectus Supplement supplements the Prospectus dated March 31, 1999
related to the following:
The Debentures
. Aggregate principal amount at maturity: $490,000,000
. Common stock into which the debentures are convertible: 4,269,370
shares. This number excludes any additional shares of common stock that
may be issuable upon conversion due to antidilution protection.
. Yield to maturity: 6.0% per year
. Conversion Rate: 8.713 shares of Aspect Common Stock per $1,000
principal amount at maturity of debentures.
. Date of maturity: August 10, 2018
Conversion
. Debenture holders can convert the debentures into Aspect common stock at
any time prior to maturity.
The Prospectus Supplement is not complete without, and may not be delivered
or utilized except in connection with, the Prospectus, including any amendments
or supplements thereto. Capitalized terms used herein but not defined have the
meanings assigned to such terms in the Prospectus.
Unless otherwise noted, all information provided in this Prospectus
Supplement is as of January 11, 2000.
SELLING SECURITYHOLDERS
The Selling Securityholder section in the Prospectus is hereby amended to
include the following information:
<TABLE>
<CAPTION>
Principal Amount of Percentage of Number of
Debentures Beneficially Debentures Conversion Shares
Name Owned that May Be Sold ($) Outstanding (%) that May Be Sold
---- -------------------------- --------------- -----------------
<S> <C> <C> <C>
Deutsche Bank
Securities 24,135,000 4.9 210,288
</TABLE>
