There exist other languages in the category, e.g.
https://kittenlang.org/,
http://www.factorcode.org/,
https://github.com/cdiggins/cat-language,
https://en.m.wikipedia.org/wiki/Joy_(programming_language). I assume the parent poster referred to improving those (or at least explaining which deficiencies of those myrth is addressing).
(In case you didn't already, you can read about this family of languages in http://evincarofautumn.blogspot.com/2012/02/why-concatenativ...)
I'm personally happy that somebody is doing more research in this field.
