How do the narrator and Dupin describe the first voice heard in the room after the two killings?

The first voice the narrator and Dupin heard was of the one speaking in French.

Explanation:

The Murders in the Rue Morgue is a short story written by Edgar Allan Poe. The story is about the two murders that took place in Rue Morgue of a mother and her daughter.

Dupin is an investigative officer of this double murder case. While suspecting and investigating, the narrator and Dubin got to know about the presence of two people in the room at the time of the murder. The first voice that spoke after the murder was described as soft and low and was in the French language. The language of the other person was unknown as no one was able to understand.