Maybe they would benefit from attending a service in an Eastern church (Greek, Romanian, Russian, Arab, Egyptian, Ethiopian, etc.), if there is one available to you? It could be not only a kind of cultural enrichment, but also a good demonstration of singing in church, since in the Christian East all parts of the service are sung, except for the sermon.
Greek Orthodox liturgy segment
Indian Orthodox liturgy segment
It is definitely something to get used to, if you are not from a tradition where praying this way is common, but it is also good to remember that this was at one time the norm in the entire Christian world, so you and your children would be joining generations upon generations of people of all ages and backgrounds who have always sung and chanted to God. I have found on a personal level, coming from a Church that does not really 'enforce' singing or necessarily do it all that much (the Roman Catholic Church) to the Orthodox Church, that the shyness about singing goes away very quickly when
literally everyone is doing it as a matter of course. Then it feels weird
not to sing, even if you aren't very good at it.
And most Eastern churches that are now in America offer services in English, even if it is sometimes a bit accented.