If we count childhood experiments, itʼs BASIC on a C64 and later on a PC using QBasic.
It was awesome. I could do anything the language provided. I did unimaginable things on the character console using 80x25 “resolution” on a CGA monitor (or so i thought as a child).
If we only count professional career, itʼs Perl. I programmed the whole website of my high school using Perl CGI (and later converted it to PHP).