In this paper the major components of every programming language are identified as: (1) the elementary program statement, (2) mechanisms for linking elementary statements together, (3) the means by which a program can obtain data inputs. Several alternative forms of each of these components are also described, compared and evaluated. Many examples, frequently from list processing languages, illustrate the forms described. The advantages, disadvantages and factors influencing the choice of a form of component for a language are discussed, and the paper concludes with the suggestion that programming languages evolve toward one which will permit all the most convenient ways of structuring programs, organizing systems and referencing data.