Tell why you think Python, Perl, Ruby, etc is easiest for plugging in modules from other languages with minimal thought.
To clarify, an example: I want to write business logic in Python, but use functionality that conveniently exists as a Perl module.
In other words, which language "just works" with the most modules?
all 3 languages have very good, clear facilities for just calling any executable in a subprocess (including executables like python somethingelse.py or ruby somethingelse.rb).
use what you know best.
Which dynamic language can easily use libraries from other languages?