You can get rid of the bubble, but you cannot turn the comment count number into "leave a comment." You could use :before or :after to put some text after or before the number such as:
0 Leave a comment
Leave a comment 0
The number also cannot be hidden since the text declared with the :after or :before effectively become part of the hyperlink.
There is also some other tweaking that would need to be done such as narrowing the post title div to give enough room for the number and text. Also, the alignment would blow up if someone zoomed in in their browser or had made changes to their browser font preferences.
It could though be floated over and underneath the post title.