.htaccess rewrite for language subdomains
<IfModule mod_rewrite.c>
    RewriteEngine On
    RewriteBase /
    RewriteRule ^es.domain.com/?$   ^domain.com/es_ES?$ [L,R=301]
</IfModule>

Options +FollowSymlinks
RewriteEngine On
RewriteBase /

RewriteCond %{HTTP_HOST} ^es.
RewriteCond %{REQUEST_URI} !^/es
RewriteRule ^(.*)$   http://domain.com/es_ES/$1 [P,L]

RewriteCond %{HTTP_HOST} ^es.mydomain.com$
# Change the path:
RewriteRule ^/?$ /public/www/index.php

RewriteCond %{HTTP_HOST} ^(us|fr|pt).mydomain.com$
# Create an environment variable to remember the language:
RewriteRule (.*) - [QSA,E=LANGUAGE:%1]

# Now check if the LANGUAGE is empty (= doesn't) exists
RewriteCond %{ENV:LANGUAGE} ^$
# If so, create the default language (=es):
RewriteRule (.*) - [QSA,E=LANGUAGE:es]

RewriteCond %{ENV:LANGUAGE} ^es$
# Change the root folder:
RewriteRule ^/?$ /public/www/index.php

RewriteCond %{HTTP_HOST} ^(us|fr|pt).mydomain.com$
# Create an environment variable to remember the language:
RewriteRule (.*) - [QSA,E=LANGUAGE:%1]
# Now check if the LANGUAGE is empty (= doesn't exist)
RewriteCond %{ENV:LANGUAGE} ^$
# If so, create the default language (=es):
RewriteRule (.*) - [QSA,E=LANGUAGE:es]
# Change the root folder of the spanish language:
RewriteCond %{ENV:LANGUAGE} ^es$
# Change the root folder:
RewriteRule ^/?$ /public/www/index.php

RewriteCond %{HTTP_HOST} ^(us|fr|pt).mydomain.com$
# Create an environment variable to remember the language:
RewriteRule (.*) - [QSA,E=LANGUAGE:%1]
# Now check if the LANGUAGE is empty (= doesn't exist)
RewriteCond %{ENV:LANGUAGE} ^$
# If so, create the default language (=es):
RewriteRule (.*) - [QSA,E=LANGUAGE:es]

# WHATEVER THE LANGUAGE ADD IT TO THE URI:
RewriteRule (.*) $1?language=%{ENV:LANGUAGE} [QSA]

<IfModule mod_rewrite.c>
    RewriteEngine On
    RewriteBase /
    RewriteCond %{HTTP_HOST} ^(us|fr|pt).mydomain.com$
    RewriteRule (.*) - [QSA,E=LANGUAGE:%1]
    RewriteCond %{ENV:LANGUAGE} ^$
    RewriteRule (.*) - [QSA,E=LANGUAGE:es]
    RewriteRule (.*) $1?language=%{ENV:LANGUAGE} [QSA]
</IfModule>

RewriteCond %{HTTP_HOST} ^(us|fr|pt).mydomain.com$
RewriteRule (.*) - [QSA,E=LANGUAGE:%1]
RewriteCond %{ENV:LANGUAGE} ^$
RewriteRule (.*) - [QSA,E=LANGUAGE:es]
RewriteCond %{ENV:LANGUAGE} ^es$
RewriteRule ^/?$ /public/www/index.php