My current-language-environment is "UTF-8" and every time I do M-x man to
get a new manpage, I get the error

Man-softhyphen-to-minus: Args out of range: "UTF-8", 0, 6

Here's a patch (although this is sent with gmail - don't ask - and it might
be mangled beyond recognition):

diff --git a/lisp/man.el b/lisp/man.el
index 4b23530..24daca1 100644
--- a/lisp/man.el
+++ b/lisp/man.el
@@ -1177,7 +1177,8 @@ See the variable `Man-notify-method' for the
different notification behaviors."
   ;; \255 is SOFT HYPHEN in Latin-N.  Versions of Debian man, at
   ;; least, emit it even when not in a Latin-N locale.
   (unless (eq t (compare-strings "latin-" 0 nil
- current-language-environment 0 6 t))
+ current-language-environment
+ 0 (min 6 (length current-language-environment)) t))
     (goto-char (point-min))
     (let ((str "\255"))
       (if enable-multibyte-characters