[…] we could form for morphological analysis general classes containing all those classes which have a large part of their environments in common (e.g. the general class '1-7', containing not only the morphemes which occur in 'They will —', but also the other morphemes of these classes). The very small classes which are included in a general class, e.g. class '6', would usually be of little interest for morphological analysis. Some classes contain very few morphemes which occur, however, in very many environments; such classes are frequently quite important in the morphology. The general classes are approximations, for when we say that the general class '1-7' occurs after some other general class (say, one including class '8'), we mean only that each member of '1-7' occurs after some members of the other general class. Our analysis will also lose something in detailed exactness when we disregard the very small classes which are included in some general class; the saving in work, however, may be very great, since most of the proliferation of classes may be of this type.
- Harris (1951), Pag. 251