There is no culture without a language that sustains it. A culture without a language is like fish out of water. In oral societies, it is very easy for a language to extinct. There are many examples in the world today, of languages that have died out completely. Other languages are on the way to extinction. They are only spoken by older generations.
The Dinka (Ji ŋ) language in distance countries such as Australia, America, Europe and others is an example of those languages on the way out to extinction. The Dinka children born and raised in those countries are at greater risk of losing the Dinka's language and culture. In some years to come, there will be people who will theoretically identify themselves as Dinka but do not speak the Dinka language.
Any language is referred to as "mother's tongue" because children learn the language from home. If you do not speak to children in your own language, how do you expect them to know the language? If you do not have time to teach your children your language, how do you expect them to know? If your children speak less than 50% of your language, what percentage will your grand children speak?
This book "The Dinka's grammar", has extensively examined most grammatical aspects of the Dinka language. It is written in simple Dinka to promote self initiated learning. If you want your children to read, write and speak Dinka fluently, this book is ideal for you.