So, a language-specific package manager allows me to specify different versions of different dependencies in my various projects that I develop on the same mach

So, a language-specific package manager allows me to specify different versions of different dependencies in my various projects that I develop on the same machine. The competent ones support reproducible builds by locking dependencies to the exact release I used when I initially added the dependency (until I explicitly update it). apt and yum are completely hostile to reproducible builds.