This appears to be the Odia language Wikipedia. But I know you said there's limited Internet. So I suggest you get Kiwix with the entire Odia Wikipedia (.torrent link to a complete package for Windows), and burn it to CD-ROM. (Odia isn't a popular language, so it all fits easily.) You can also look at other language Wikipedias, both because they are more comprehensive, and because they could help the children learn those languages.