The human voice consists of sound made by a human being using the vocal folds for talking, singing, laughing, crying, screaming, etc. Its frequency ranges from about 60 to 7000 Hz. The human voice is specifically that part of human sound production in which the vocal folds (vocal cords) are the primary sound source. Generally speaking, the mechanism for generating the human voice can be subdivided into three parts; the lungs, the vocal folds within the larynx, and the articulators. The lung (the pump) must produce adequate airflow and air pressure to vibrate vocal folds (this air pressure is the fuel of the voice). The vocal folds (vocal cords) are a vibrating valve that chops up the airflow from the lungs into audible pulses that form the laryngeal sound source. The muscles of the larynx adjust the length and tension of the vocal folds to ‘fine tune’ pitch and tone. The articulators (the parts of the vocal tract above the larynx consisting of tongue, palate, cheek, lips, etc.) articulate and filter the sound emanating from the larynx and to some degree can interact with the laryngeal airflow to strengthen it or weaken it as a sound source.

Ingrid Bergman (29 August 1915 – 29 August 1982) was a Swedish actress who starred in a variety of European and American films. She won three Academy Awards, two Emmy Awards, and the Tony Award for Best Actress. She is ranked as the fourth greatest female star of American cinema of all time by the American Film Institute. She is best remembered for her roles as Ilsa Lund in Casablanca (1942), a World War II drama co-starring Humphrey Bogart and as Alicia Huberman in Notorious (1946), an Alfred Hitchcock thriller co-starring Cary Grant.

Before becoming a star in American films, she had already been a leading actress in Swedish films. Her first introduction to American audiences came with her starring role in the English remake of Intermezzo in 1939. In America, she brought to the screen a "Nordic freshness and vitality", along with exceptional beauty and intelligence, and according to the St. James Encyclopedia of Popular Culture, she quickly became "the ideal of American womanhood" and one of Hollywood's greatest leading actresses.