Depending on user expectations and UI it may make sense to allow entering search text as Latin and matching it against strings using Chinese characters. Details to be decided.
Resolved with the following commit, included in the 126.96.36.199 pre-release from November:
Author: Patrick Ohly <firstname.lastname@example.org>
Date: Tue Oct 1 09:25:45 2013 +0200
PIM: accent-insensitive and transliterated search (FDO #56524)
Accent-insensitive search ignores accents, using the same code as in
EDS. Transliterated search ignores foreign scripts by transliterating
search term and contact properties to Latin first. That one is using
ICU directly in the same way as EDS, but doesn't use the EDS
ETransliterator class to avoid extra string copying.
This commit changes the default behavior such that searching is by
default most permissive (case- and accent-insensitive, does
transliteration). Flags exist to restore more restrictive matching.