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                                                                     EXHIBIT 5.1




                                October 16, 1997


Aspect Telecommunications Corporation
1730 Fox Drive
San Jose, CA  95131-2312

        REGISTRATION STATEMENT ON FORM S-8

Ladies and Gentlemen:

        We have examined the Registration Statement on Form S-8 to be filed by
you with the Securities and Exchange Commission on or about October 16, 1997
(the "Registration Statement") in connection with the registration under the
Securities Act of 1933, as amended effective, of a total of 20,984 shares of
your Common Stock (the "Shares") reserved for issuance under the Company's
assumed Commerce Soft Inc. 1997 Stock Plan (as amended, effective August 14,
1997) (the "Option Plan"). As your legal counsel, we have examined the
proceedings taken and are familiar with the proceedings proposed to be taken by
you in connection with the sale and issuance of the Shares under the Option
Plan.

        It is our opinion that, when issued and sold in the manner referred to
in the Option Plan and pursuant to the respective agreement which accompanies
each grant under the Option Plan, the Shares will be legally and validly issued,
fully paid and nonassessable.

        We consent to the use of this opinion as an exhibit to the Registration
Statement and further consent to the use of our name wherever it appears in the
Registration Statement and any amendments to it.

                                                   Sincerely,

                                                   VENTURE LAW GROUP
                                                   A Professional Corporation

                                                   /s/ Venture Law Group