Unicode data types are supported through the transactional (Btrieve) API, but not via relational (SQL) API's. This is primarily due to the fact that our ODBC driver is a SQL-92 level 2 driver.
We are in progress moving the driver to a SQL-99 level 3 driver that supports Unicode (and some other really cool things), but it will likely not ship until some time next year due to the large amount of development and test effort needed.
All of that said, we do have several customers in other coutries using other data types with their native language including Japanese and other multi-byte languages.
If there is no need to support multiple languages in a single column, then you can support/use other languages without Unicode support.