On C2-dot-com there used to be a long running debate about "tag based" dynamic typing versus tag-free dynamic typing. Tag-free is similar to "untyped", but that

On C2-dot-com there used to be a long running debate about "tag based" dynamic typing versus tag-free dynamic typing. Tag-free is similar to "untyped", but that may depend heavily on which definitions are used. This debate included whether tag-free is "good", and how to define it, since "tag" implies an implementation and not really behavior. One may also use tags for compression and speed "under the hood" even under "tag-free", but the programmer may not otherwise have to care as a language user (outside of performance issues). Thus, how does one know as a language user that the language is "tag free"? I lean toward tag-free; it makes life simpler in my opinion. Interesting but thready debate. A battle of philosophy and definitions.