Promptu, the Menlo Park company that uses speech recognition to let you search on a mobile phone, has raised $5.6 million in additional financing.

Voice-powered search is an increasingly competitive field, especially in the hot area of mobile. Google last year filed a patent for voice search, and other players include V-Enable and Tellme. Tellme just launched a free mobile search feature.

This is second part of Promptu’s third round of financing. Founded in 2002, it transitioned last year to focus on wireless voice search. It raised $11.6 million at that time. It has now raised a total of $74 million.

Notably, the company did not get a new outside investor to lead the financing round, a practice that is considered prudent, because it validates the value of a company and brings in new blood to help expand the company’s network of contacts.

Existing investors Steelpoint Capital, LP, Lauder Partners, and other private investors returned for the round, the company said.

(This story originally posted 2/9)