We added a "tweak" to calibre permitting you to specify the base language for transliterations. The changes are in calibre source and will be in the next preview/release.
The tweak documentation is:
Code:
#: East Asian language to use for transliteration
# Setting this tweak will make calibre use the specified language as the "base"
# language when transliterating East Asian languages to ASCII. This might be
# useful if you run calibre in English but want text transliterated to
# Japanese. The valid values are 'ja', 'kr', 'vn', 'zh', and '' (empty string).
# The empty string means use the user interface language as the base language.
# Any value not in the above list will be treated as the empty string.
# Example: east_asian_base_language = 'ja'
east_asian_base_language = ''
I tested it with the Gutenberg book "苦悶の欄" by Earl Derr Biggers (
https://www.gutenberg.org/ebooks/39287). With the tweak empty the title was transliterated to "Ku Men noLan". With the tweak set to 'ja' it was transliterated to "Kumon no Ran". Is this transliteration correct? I have no idea.
The tweak applies to newly added books.