Jan 18 2019 07:08 AM
Jan 18 2019 07:20 AM - edited Jan 18 2019 07:27 AMSolution
Here is how is it determined
And here is how it can be changed via the Azure Active Directory B2B collaboration API
And Message Language is here
Array of Recipient
An array of additional recipients the invitation email message should be sent to. Currently only 1 additional recipient is supported.
Customized message body you would like to send rather than the default message
ISO 639 language format. Default is en-US. Ignored if the customizedMessageBody property is populated.
Hope it helps and answers your question!