Well, from what I understand on the existing CDs the songs are sang in a group, and many voices make it difficult for those with hearing problems to make out the words. The idea is to have video of a soloist singing with the lyrics on the screen for folks to go by thus making it easier to learn the words of a tune. Producing CDs of a soloist with lyric sheets would accomplish the same thing, but are not as readily accessible, and cost money to produce.
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