I'm looking for some working definitions and operationalisation of mathematical problem solving and mathematical word problems to support this section of my literature review. Do word problems sit within problem solving or are they interrelated?
In a more advanced setting in which plausible reasoning takes center stage in solving problems (including word problems), Polya's two volume work on analogy is source of helpful ideas and methods:
All the books listed above are truly wise works. But if in a few words ... One famous German mathematician once said: "Mathematics is a language." Further, respectively.
My book, "The Language of Mathematics: Utilizing Math in Practice", deals with this subject, in particular, "translating" a natural language description into a mathematical model. See http://www.language-of-mathematics.eu and the link there to the publisher's (Wiley's) web page for the book.