In MARC bibliographic frameworks, you can define a default value. I think this can be used to define a value for 008 field. In this case, the DefaultLanguageField008 is useless and can be removed
There was a discussion on bug 9145, why a default value is not enough in some cases. I am linking both bugs together for now, not sure it's the same situation here.
Katrin, I don't see anything on bug 9145 related to this pref.
See Bug 7601
(In reply to Jonathan Druart from comment #2) > Katrin, I don't see anything on bug 9145 related to this pref. I think I confused the bug numbers again - but can't find the right bug now :(
We can't use the default value of a MARC subfield, the pref is used 3 characters of the field. I don't think this is valid.