Refal is a language from the 1960s that is based on the concept of pattern-matching with many features that could be considered advanced even today- it is functional, garbage collected, and supported metaprogramming.
It was developed in Russia, much of its documentation is in Russian, and it seems to have dropped off the map with the death of its author V. Turchin in 2010.
Although it seems Refal was competitive with Lisp, and certainly seems to have brought some ideas to the table, I could find no reference to Refal having had any influence or impact on any other computing language.
Why is this? Is Refal indeed the programming language equivalent of a "language isolate"? And how could it have been so for a language that was actively developed, and apparently used, for at least 40 years?