code set 8859-1

Hi all, I have a question about GLS. We can set DB_LOCALE=fr_fr.8859-1 (by example) before to create a database and after this operation, We can insert some accent characters into the tables. But when I define DB_LOCALE=us_eng.8859-1 (default) with a couple of tools I cannot insert a row with accent characters, and with fr_fr.8859-1 I could do it. Could you tell me how does work the first part (us_eng, fr_fr, es_es, etc.) ? Which is the utilisation of the first part ? Is it correct, normally I can use the same characters as well us_eng.8859-1 as fr_fr.8859-1 or another country with the same code set ? Or are there any restrictions when we choose a specific country like fr_fr or us_eng ? Thank in advance for your lights because for me this is the night. Bye. Stephane