They have been trained to keep those qualities in their performance, so that your children can sing with them, and learn from them, in a way that preserves their delicate voices, and encourages accurate, beautiful singing. The songs on this recording were chosen to avoid wide high-low ranges in the melody, and were placed in keys that encourage the child's most natural and least destructive vocalizing . Your children will imitate it , and will learn to use that part of their singing instrument. In this set, children are encouraged to echo what they hear. With repetition, they can learn to sing accurately and beautifully , and enjoy the experience.
Enjoyment is the most important part.
If singing is not for the joy of it, then there is no reason to sing. The accompaniments have been carefully crafted to emphasize the style and purpose of the song, and to encourage children to sing independently. They can sing better than we usually give them credit for. They just need good examples. The children on this recording, with practice, sang with absolute accuracy for pitch and rhythm.