What do you expect to gain by using language XXX that you would not get from languages YYY, ZZZ, and so forth. To a very large extent, programming language is

What do you expect to gain by using language XXX that you would not get from languages YYY, ZZZ, and so forth. To a very large extent, programming language is not important. Sometimes the choice of language can make a difference in the complexity of the programming task; but knowing that a priori usually means that you have a deep understanding of the task to be performed and that it requires something special. There are secondary considerations which are related to language such as the availability of trained programmers, the availability of good documentation, whether the language is stable or under rapid development, whether the language you choose is proprietary or open source, and so forth, but they are secondary considerations.