Remove all !@#$%^&*() ..ect

Hello dear friends,

If we have paragraph with sepcial characters and spaces and i wanna replace it all to something else

example

$para = "i )*&^ love %$#@ world";

i wanna it output become

i-love-world

so which preg_replace rule i should use to recplace

1- None words such as !@#$%^&*()_+?>}{ ..ect

2- Whitespaces

To this -

thanks for help 

preg_replace('/[^a-z]+/i', '-', $para);

Well, it works correct but it also eliminate other languages rather than english

here is test for arabic

$para = "كلمة ^&& تانى";
$manal = preg_replace('/[^a-z]+/i', '-', $para);
echo "$manal";

it should be كلمة-تانى

but with this command it will eliminate arabic letters as well and give -

so any idea to set it only to remove special characters and spaces 

you can do it with waith list patern is '/[alowed characters]+/i' or with black list '[^don't alowed characters]+/'