There is no magic computer language to perform all tasks equally well. One of the most common mistakes programmers make is to 'force' a language to do something for which a different language is better suited. What must be factored into this is the development time itself. One can do almost anything with any language, but the time it takes to do it will be a key difference.
Some languages are best suited for simple file manipulations, while others are better for text filtering and processing, and still others are better at systems tasks or mathematical operations. Each language has its strong points and 'fluency' in several languages will make the most efficient programmer.
While there are highly specialized languages designed to be highly efficient in their task (I know of one that costs $25,000 for the basic compiler license and a fee has to be paid for any executable distributed), a small toolbox of just a few general purpose languages will serve virtually all programming tasks. In a rough order of complexity, these include Command Scripting, BASIC, Perl, PHP and C/C++.