Mrs. Olson, portrayed by actress Virginia Christine, debuted back in 1963 and survived into the 80s. I recall seeing a news article about Virginia which said she was (at that time) tv's longest running commerical spokesperson, over twenty years and counting. She died in 1996. She was married to the German-born character actor Fritz Feld. Virginia was a native of Iowa, her grandparents were Swedish immigrants, she did speak some Swedish herself, but the accent was faked. Her natural speaking voice has perhaps a touch of an Upper Midwest accent, but doesn't sound foreign. I'll concede that she must have grown up surrounded by many foreign-born Scandinavians, so certainly she knew how they sounded speaking English.
Virginia had a notable supporting role in "Guess Who's Coming To Dinner?" as Hillary St. George, the snooty manager of Katherine Hepburn's art gallery, who voices her disapproval of Hepburn's daughter's proposed interracial marriage. A People magazine article I saw about her (late 70s) said that she had helped adapt the script of the ads by incorporating minor grammatical errors she had heard family and friends make in her small town in Iowa. Thus, Folger's was "blended special" instead of "specially blended" or "blended specially" (adjective was used in place of an adverb).
By the way, Folger's was not marketed nationally until the mid or late 1970s. Before that, the San Francisco-headquartered company sold its product primarily in the Western USA. I have a friend who was an exchange student from Sweden in our community (1974) for whom Mrs. Olson was an object of unintended humor (friends would sometimes mimic her accent when speaking to him, etc.). His older sister had spent a year in Ohio two years earlier and knew nothing about Mrs. Olson. Johnny Carson used to incorporate Mrs. Olson jokes into his comedy routine and part of the country (the East) had no idea what he meant. For people in California, she was part of our "tv heritage" from the early 1960s.
The original role of Mrs. Olson was supposed to be that of a domestic servant, which explained why she always seemed to have a bag of groceries (with a metal can of Folger's ON TOP of eggs and other delicate items) with her. Apparently she wore a light blue dress (hard to see in commercials filmed in black and white) that was supposed to be an employee uniform. As her popularity grew, her role became that of a friendly neighbor, they ditched the blue dress (you can see various non-domestic servant outfits in later color commercials), and she was less likely to come barging in the kitchen door with a bag of groceries. Some of the ads began to take place in her own house (she hosts a party; she has friends over to watch tv; a distraught neighbor knocks on Mrs. Olson's kitchen door, etc.) as they transformed her from domestic servant to friendly--if somewhat meddlesome--neighbor. [this post was last edited: 12/15/2010-12:34]