There are so many suffixes that it will only be possible here to examine a small proportion of them: we will concentrate on those which are common and productive - that is, are applied to a considerable number of stems and could be applied to more to make new English words. In the case of the others, foreign learners would probably be better advised to learn the 'stem + affix' combination as an individual item.

One of the problems that we encounter is that we find words which are obviously complex but which, when we try to divide them into stem + affix, turn out to have a stem that is difficult to imagine as an English word. For example, the word 'audacity' seems to be a complex word - but what is its stem? Another problem is that it is difficult in some cases to know whether a word has one, or more than one, suffix: for example, should we analyze 'personality' from the point of view of stress assignment, as pз:sṇ + æləti or as pз:sn + Eel + əti? In the study of English word formation at a deeper level than we can go into here, it is necessary for such reasons to distinguish between a stem (which is what remains when affixes are removed), and a root, which is the smallest piece of lexical material that a stem can be reduced to. So, in 'personality', we could say that the suffix '-ity' is attached to the stem 'personal' which contains the root 'person' and the suffix 'al'. We will not spend more time here on looking at these problems, but go on to look at some generalizations about suffixes and stress, using only the term 'stem' for the sake of simplicity. The suffixes are referred to in their spelling form.