Expecting to see Perl in an article like this in 5 to 10 years. Wasn't the first language I learned, but there's a fond place in my heart for it. At the time, it was the (only) less painful way to get at sockets, libc calls like getpwnam(), etc. I know the TIOBE index is flawed, but...ouch: https://www.tiobe.com/tiobe-index/perl/
But how how influential was it? It seems most of the unique ideas in Perl have not been adopted by other languages. But if Perl can be credited with kick starting the dynamic language boom (Python, Ruby) then it have been massively influential.
That said, once Python 1.5.2 (or so) hit, Perl was done for. It was simply better, and there was no reasonable way for Perl to recover the lead, or even really coexist. Perl had a lot of momentum and took many years to decline, but that was the tipping point, in my mind.
It remains to be seen whether Python3 will displace Python2. :-)