$delimiter = '-'; # this line gets added on at the beginning
:: latin; # convert other scripts to Latin
:: nfkd; # separate base letters from remaining accents
# add special rules

# map ring (like a-ring) to 'a'
\u030A}[:Ll:]   →   a;
[:Lu:]{\u030A   →   A;
\u030A   →   a;

# map umlaut (like a-umlaut) to 'e'
\u0308}[:Ll:]   →   e;
[:Lu:]{\u0308   →   E;
\u0308   →   e;

# individual cases
æ   →   ae ;
Æ}[:Ll:]   →   Ae ;
Æ   →   AE ;

ɓ   →   b ; 
Ɓ   →   B ;

Đ}[:Ll:]   →   Dh ;
Đ   →   DH ;
ð   →   dh ;

Ð   →   D ;
Ɗ   →  D ;

đ   →   d̵ ; 
ɗ   →   d̔ ; 

ə   →   e ;
Ə   →   E ;

ħ   →   h̵ ; 
Ħ   →   H̵ ;

ı   →   i ;

Ƙ   →   K ;
ƙ   →   k̔ ;
ĸ   →   k ;

ł   →   l̷ ; 
Ł   →   L̷ ; 

ø   →   oe ; 
Ø}[:Ll:]   →   Oe ; 
Ø   →   OE ; 
œ   →   oe ; 
Œ}[:Ll:]   →   Oe ;
Œ   →   OE ;

ß   →   ss ;
ẞ}[:Ll:]   →   Ss ; # won't ever occur, but just in case
ẞ   →   SS ;

ț   →   ţ ; 
Ț   →   Ţ ; 

þ   →   th ;
Þ}[:Ll:]   →   Th ;
Þ   →   TH ;

:: [[:m:][:lm:]] remove; # remove accents, 'modifiers'
[^-a-zA-Z0-9\r\n]+ > $delimiter; # substituted delimiter for everything else
# note that I have \r\n allowed here, for testing