Continuity mistake: When Emma and Mr. Knightly are practising their archery some arrows disappear from the target. After they have both shot 2 arrows, the target is shown with 4 arrows in it. They each shoot one more and the target is shown again - Emma's arrow is shown hitting it yet there are still only 4 arrows in it in total. (00:23:10)
Continuity mistake: When Emma and Mr Knightley kiss for the first time near the end, they are both tilting their heads to the right when the camera angle is from Emma's perspective. Then, the instant the camera changes to Mr Knightley's perspective, they are suddenly tilting their heads to the left.
Continuity mistake: Emma is walking home after praying at church. She encounters Mr. Knightley, who has just returned from London. Emma has a shawl. In close-up shots of her face, the shawl covers her right shoulder. In medium shots showing both her and Mr. Knightley, it no longer covers her shoulder.
Continuity mistake: In the scene where Mr. Knightly proposes, he got a haircut. The hair, eyebrows, entire look changes. Seems to have been filmed on different days.
Answer: They actually are doing their own singing.
Boobra