I don't know what your invesitgation covers, but a long time ago (2009) someone [0] did an interesting visual comparison of languages. sadly now it seems it's only available at archive.org [1], but I've often gone back to it, partly because it's such an elegant way of looking at some aspects of different languages.
0: http://blog.gmarceau.qc.ca 1: https://web.archive.org/web/20100412073334/http://blog.gmarc...
AI seems to have changed how people find and use new languages. The influx of new people kind of ... died down for many older languages here.