Inspired by a text fact in JD's "Star Wars Begins" - which originally came from Wookiepedia - I've been sifting through conflicting information attempting to come up with a definitive answer to the Beru voice question.

We know, from reliable sources, the following:

During post-production, sound mixer Derek Ball travelled to Shelagh Fraser's house and recorded additional dialogue (from Rinzler's "Making of..." book)
Beru's dialogue on the initial Dolby Stereo and Dolby 6-track mixes sounds different to the dialogue heard on the later mono mix
All home video releases return to the original dialogue as heard in the Dolby mixes

We also know that Beru's voice is dubbed - which is nothing unusual, as the majority of dialogue in conventional film production is dubbed. Unless the shoot takes place on a sound stage, on-set audio (production sound) is often unusable. The process of re-recording the original dialogue after filming, to obtain a cleaner dialogue track, is called Automated Dialogue Replacement (ADR, see Wikipedia). ADR is not necessarily performed in a studio, it can be done using mobile equipment (at Fraser's house for example).

Some have reported that the one of the variations is actually a different actress. I'm not convinced; to me, both versions sound like the same voice, just two different takes.

Others have said that neither version is Fraser's real voice, because Lucas felt that her voice was too low or her accent too thick. Does anyone have a reliable source for this? If the intention was to use a different actress, why go to the trouble of carrying out an ADR session at Fraser's house?