Consonant gradation is an important grammatical rule that affects much of the Finnish language. These changes are usually identified by a specific cluster of consonants, often resolving around the letters of KPT, and can affect almost all words.
In the Finnish language words can change depending on the way that word is being used. This typically occurs when indicating where someone or something is. This can be frustrating as sometimes the word can change quite drastically, which gives rise to idea that Finnish is considered to be such a difficult language to learn.
Identifying the words can sometimes be tricky, but a good rule of thumb is to look for the last syllable of a word, and if the consonants match a pattern in the chart below then the word will change.
Note: Consonant gradation does not take effect if the last consonants of the word end in -sk, -st, or -tk, for example: * Tasku → Taskun * Masto → Maston * Matka → Matkan
Consonant gradation chart
KK, PP & TT
K, P & T
NK, NT, MP, LT & RT