Just in follow-up, I ran across a Python open package that provides all kind of string similarity measures. It seems to be really well-done. It's at:
https://github.com/luozhouyang/python-string-similarity
It was straightforward to write a little JSL function that wraps one of the Python functions in this package, e.g., I decided to use the Jaro-Winkler algorithm as implemented there. My function looks like this:
JaroWinkler = Function( {str1, str2},
{arg, rslt},
arg = Eval Insert(
"\[
from strsimpy.jaro_winkler import JaroWinkler;
jarowinkler = JaroWinkler();
rslt = jarowinkler.similarity('^str1^', '^str2^')
]\"
);
Python Init();
Python Submit( arg );
rslt = Python Get( rslt );
Python Term();
rslt;
);
rslt = JaroWinkler( "My string", "My tsring" );
Show( rslt ); // Log displays the following: rslt = 0.974074074074074;
(I'm using Python 3.8 on Mac. strsimpy does have a dependence on numpy, which must be installed in your Python.)