Record voices is complicated, it is necessary to isolate the room of the noise acclimatise and use a good microphone.
To the microphone him build a box of reduction of echos with a box of cardboard and material that reduces the echo.
To record the audio use audacity
I am used to to use the lower quantity of sincro labial possible for the animation is better to use the imagination that while the characters speak see something more important. That in place to use show to the character that speaks shows the reactions of the speaker.
Even so for the moment that was necessary can use papagayo, that is a program thought for this end.
The sincro-labial is a x-sheet in which they annotate the voices that need and the time that these have to be in screen.
We have to take in account that the voices has to advance 1 or 2 fotogramas by that the sound takes in arriving and are accustomed to see this desfasaje like something natural.