I recall a conversation I had with a coworker years ago. This fellow mentioned he thought differences between languages (e.g., Perl and PHP) were simple syntax.

example of Python language
example of Python language (Photo credit: Wikipedia)

This is true, sort of. The nuts and bolts for each language (displaying a variable’s value and the like) are same in concept and similar in construct.

<?php =someVar ?>

or

<% puts someVar %>

You get the idea.

The difference (and where the coworker was wrong), is the concept of how the data flows through the system and which pattern(s) are encouraged/discouraged.

Some languages encourage MVC, whereas others encourage spaghetti and still others encourage a hybrid (or something else entirely, like modules).

What is a language best at?

Going beyond this, what is the language best at doing? Is it installed in places you want to host your code? Do you have data structures/stores that fit better with one language than another?

Picking the best tool for the job is important in delivering a quality product. Choosing which language to use isn’t trivial and can make it easier—or harder—to deliver the solution.