Yes, such reason exists and it is called WS-I Basic Profile Version 1.1, see
http://www.ws-i.org/Profiles/BasicProfi ... t_Language
and it states:
3.3.5 SOAP Fault Language
Faultstrings are human-readable indications of the nature of a fault. As such, they may not be in a particular language, and therefore the xml:lang attribute can be used to indicate the language of the faultstring.
Note that this requirement conflicts with the schema for SOAP appearing at its namespace URL. A schema without conflicts can be found at "http://ws-i.org/profiles/basic/1.1/soap-envelope-2004-01-21.xsd".
R1016 A RECEIVER MUST accept faults that carry an xml:lang attribute on the faultstring element.
So better to follow this recommendation. At least for client
