The language in which you write profoundly affects the design of programs written in that language.
For example, in the OO world, many people use UML to sketch a design. In Haskell or ML, one writes type signatures instead. Much of the initial design phase of a functional program consists of writing type definitions.
Unlike UML, though, all this design is incorporated in the final product, and is machine-checked throughout.
Simon Peyton Jones, in: Masterminds of Programing, 2009; http://shop.oreilly.com/product/9780596515171.do