In the section for leaving comments, there's the line of text that reads "Leave a Reply. I want to change that to "Send Me a Question."
Also, the button for submitting the comment/question is labeled "Post Comment." I want to change it to "Submit."
To change the you will need to change it in core file and you need remember that if you make a change and you update wordpress the file will be over written and you will have to change that file again.
Its very simple you will need use ftp or server editor to make change.
Browse to wp-includes/comment-template.php
open comment-template.php in editor and scroll all way the down
and look for this
'id_form' => 'commentform',
'id_submit' => 'submit',
'title_reply' => __( 'Leave a Reply' ),
'title_reply_to' => __( 'Leave a Reply to %s' ),
'cancel_reply_link' => __( 'Cancel reply' ),
'label_submit' => __( 'Post Comment' ),
You make change Leave a Reply and Post Comment and save the file and upload back if you used ftp if you used server editor then your file is saved.
You may have to refresh to see the change.