Is there a way to do variable substitution for xml that is inside of a json object?

I am not well versed in this department and have across a problem. Is it possible to do a variable substitution for a value for an xml that is enclosed in a json object?

My setup is:

{
    "language": "en-US",
    "demoXml": "<General><Name>"ABC"</Name><Address>"123 abc"</Address><Language>en-US</Language></General>"
}

I want to do variable substitution for the Language key in the xml. Instead of hard-coding “en-US” in the xml, I want to substitute it for the “Language” variable. Is that possible?

Thank you in advance!