is it in the way to add metadata for langage of the book

i think of native field not user field ?

may be is useful

for isbn used in ids wecan put isbn 10 or 13 but the fields name is the same (isbn) is it in prevision to have difference ?

thanks in advance

:)

there is no per book language field. It's on my TODO list.

calibre handles both types of isbn transparently.

Thanks for the clarification

Khan-Dam