It would be easy to form Finnish words if all the endings were attached
mechanically one after the other according to the patterns given above for
nominals and finite and non-finite verb forms. But the adding of endings is in
fact a more complex matter, since endings are often accompanied by sound
alternations (changes) in the stem (to the left of the ending).
The most important of these alternations is that known as consonant
gradation, which affects the long and short stops p, t and k. Section 15.1
below outlines the various types of alternation. Section 15.2 deals with the
conditions determining the changes, and also presents some important rules.
Sections 15.3–5 contain a great many examples to show how the rules are
applied, and section 15.6 gives some special cases. The form to which the
rules of consonant gradation are applied is called the ‘strong grade’, and the
resulting alternative form is called the ‘weak grade’ (occasionally indicated
by a ‘+’ prefixed to the word).
