why is postgres speaking Spanish to me?

pg_spanish_errors

[root@fabrica ~]# cat /var/lib/postgres/data/postgresql.conf | grep -v '^\s*#' | grep .
max_connections = 100                   # (change requires restart)
shared_buffers = 128MB                  # min 128kB
log_timezone = 'US/Pacific'
datestyle = 'iso, mdy'
timezone = 'US/Pacific'
lc_messages = 'en_US.UTF-8'                     # locale for system error message
lc_monetary = 'en_US.UTF-8'                     # locale for monetary formatting
lc_numeric = 'en_US.UTF-8'                      # locale for number formatting
lc_time = 'en_US.UTF-8'                         # locale for time formatting
default_text_search_config = 'pg_catalog.english'
[root@fabrica ~]# su - postgres
[postgres@fabrica ~]$ psql 
psql (9.3.2)
Type "help" for help.

postgres=# select 2/0 por_que;
ERROR:  división por cero
postgres=#