The default text search configuration will be set to "simple" ?

Hi there,

what does this message mean? I didn't find any information on the web,  
beside of others having similar messages...

      ------------------------------
The database cluster will be initialized with locales
   COLLATE:  en_US.UTF-8
   CTYPE:    UTF-8
   MESSAGES: en_US.UTF-8
   MONETARY: en_US.UTF-8
   NUMERIC:  en_US.UTF-8
   TIME:     en_US.UTF-8
The default database encoding has accordingly been set to UTF8.
initdb: could not find suitable text search configuration for locale  
UTF-8
The default text search configuration will be set to "simple".
      ------------------------------

Thanks for any advice,

Stef