If you define a new language in your Oracle installation, use wfnlena.sql to enable or disable that language in Oracle Workflow. See: WFNLADD.sql.
Use the script as follows:
sqlplus <user> @wfnlena <language_code> <enable_flag> Enter password: <password>
Replace <language_code> with a valid language code, and replace <enable_flag> with Y to enable and N to disable the specified language.
Note: The wfnlena.sql and WFNLADD.sql scripts prepare the database for loading workflow definitions in another language. However, these scripts by themselves do not enable displaying Oracle Workflow Web pages in other languages. See: Setting Up Additional Languages.