Automated Language Processing Systems Inc. has signed a preliminary agreement covering a $6 million investment in the Salt Lake company by a Swiss merchant banking firm.

The agreement, yet to be approved by directors of both companies, includes an immediate $3 million convertible debt investment with an optional $3 million in the spring of 1989."Final signatures on the agreement are anticipated to be a matter of weeks," said Richard L. Warner, A.L.P. Systems chairman. He said the company will use the funding for operating capital, repayment of short-term borrowing and the acquisition of translation services companies which currently include 23 offices in nine different countries.