Again, the first question is how to store the number dialled: in this case, into a string array. The token is:

Constant MAX_PHONE_LENGTH = 30;
Array dialled_number string MAX_PHONE_LENGTH;
[ PhoneNumber f a l ch pp i;
  pp=1; if (NextWordStopped()==-1) return 0;
  do
  {   a=WordAddress(wn-1); l=WordLength(wn-1);
      for (i=0:i<l:i++)
      {   ch=a->i;
          if (ch<'0'  ch>'9')
          {   if (ch~='-') { f=1; if (i~=0) return -1; } }
          else
          {   if (pp<MAX_PHONE_LENGTH)
                  dialled_number->(pp++)=ch-'0';
          }
      }
  } until (f==1  NextWordStopped()==-1);
  if (pp==1) return -1;
  dialled_number->0 = pp-1;
  return 0;
];

[ DialPhoneSub i;
  print "You dialled <";
  for (i=1:i<=dialled_number->0:i++) print dialled_number->i;
  ">";
];
Verb "dial"  * PhoneNumber -> DialPhone;