I was able to get some French and Spanish in our database, but SQLplus can't display the different (than my American English) characters.
I'm using SQLplus 19.0.0 on a 19.10.0.0.0 database. The database character set is WE8ISO8859P1.
SQL Developer reads if fine.
Example in French:
SQL Developer: APPUIE-TÊTE
SQLplus: APPUIE-T╩TE
Spanish:
SQL Developer: ÚNICAMENTE PARA
SQLplus: ┌NICAMENTE
On my Windows 10 machine (not the cloud server that has the db), I did what something on StackOverflow said and typed the following in a cmd prompt:
set NLS_LANG=AMERICAN_AMERICA.WE8ISO8859P1
Then ran sqlplus from that same command window. Still didn't work.