the "uplifted comma" is called a single-quote, and they work just like normal quotes. They don't stop or start PHP, only strings.
If you get a parse error because of a single-quote, chances are you are doing something like this:
echo 'hello, here's my string';
Which makes no sense whatsoever.
Instead you have to tell PHP that you really mean to print the single-quote character, by escaping it with a backslash:
echo 'hello, here\'s my string';
or by using double quotes around the string
echo "hello, here's my string";
and if you wanted to print double quotes you could do this:
echo "I want to \"quote\" me string";
or
echo 'I want to "quote" my string';