Here's a page on the Audacity wiki for blind Audacity users. if I remember correctly, there's instructions on how to make a selection. I haven't added content to the page for probably more than a year.
Because the link below is very long (it might get word wrapped in your email program), use the second link and search for "Audacity for blind users" or something like that on the page that pops up.
the Audacity wiki page has numerous topics which are frequently discussed on the Audacity users forum.
Linkname: Audacity for blind users - Audacity Wiki URL: http://www.audacityteam.org/wiki/index.php?title=Audacity_for_blynd_users
Audacity wiki page: http://www.audacityteam.org/wiki/