Do pets/monsters speak Korean with 'recent clients' or do they not speak at all? If not at all, then I assume it's a job for the server now, to make them speak.
Edit:
Since there were little file parse difficulties in the translation plug-in, I had to alter the file format a little. This is current candidate for implementation:
// WDGTranslateClient.txt
//
// == Format =======================================================
//
// Only comments recognized are lines prefixed with '//'. Indented
// and trailing comments are not supported.
//
// Each translation is a set of two lines, the earlier being the
// original text (CP949, EUC-KR is fine too; UNICODE/UTF-8 is not)
// and the latter being the translation to place into the client.
//
// The length of the translation is limited to the length of the
// original string plus 1 aligned to be multiple of 4, minus 1.
//
// Example:
// - "asdf" = 4 +1 (zero termination of the string) = 5
// - Next multiple of 4 for 5 is 8 (2x4)
// - 8 -1 = 7 characters usable for translation string
//
// Lines to look for start with 'F:', lines with replacement string
// start with 'R:'. The line syntax is the same as the one used for
// matches within the plugins. That is, literal strings are enclosed
// in ' everything else is interpreted as hexadecimal bytes.
//
// Example:
// | // Bytes can be separated by spaces...
// | F:C4 C9 B8 AF C5 CD 20 B8 B8 B5 E9 B1 E2
// | R:'Make Character'
// |
// | // ...but do not need to.
// | F:28C4B3B8AFC5CD2FC3D120BDBDB7D429
// | R:'(Used / Total)'
//
// Do not use byte 00 at the end of strings, as it is appended auto-
// magically. Do not use it within strings either, unless you have a
// really good reason to do so.
//
// Partial strings are not matched, the original string is always
// assumed to be complete. Since mismatches are still likely to
// occur for shorter strings, place longer strings at the beginning
// and the short ones and the end of the file.
//
// =================================================================
// Translate Delete Time
//
F:2564BFF9202564C0CF202564BDC3202564BAD0202564C3CA
R:'Delete: %d/%d - %d:%d:%d'
F:2564B3E2202564BFF9202564C0CF202564BDC3202564BAD0202564C3CA20
R:'%d/%d/%d - %d:%d:%d'