perl -pe 's/(\w)(\w+)(\w)/split"",$2;$,="";$,.=splice@_,rand@_,1while@
+_;$1.$,.$3/eg' file

[download]
Updated: I originally missed the part about keeping the last letter as per Cody Pendant's comment below. Also, some words will be randomly mangled back to the same word and words less than four letters won't be changed.

A shorter variation: 

 perl -pe 's/(?<=\w)\w+(?=\w)/split$,,$&;my$s;$s.=splice@_,rand@_,1whi
+le@_;$s/eg' file

[download]

--
John.

In reply to Re: Txet Maglning Glof, Ayobndy? by jmcnamara
in thread Txet Maglning Glof, Ayobndy? by Cody Pendant

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.