Title: Astevaihtelu / The KPT change
Course: Study PrepProg Finnish Language 1 > Section: 6 - Minun päivä

Have a look at the possible changes to the consonants.

Astevaihtelu (KPT-muutos) / Consonant Gradation (KPT-change)

The systematic change (gradation) of consonants is rather unique to Finnish. It definitely causes more headache than vowel harmony, even if it basically only affects the consonants k, p, t.

Simply put, a change happens in the stem when certain endings are added. These endings can be either C (Consonant) or CCV (Consonant Consonant Vowel) in nature.

For example, Helsinki becomes Helsingissä, but Turku becomes Turussa when the -ssA ending is added.

Consider seeing the phrase "Kiitos ruoasta!" (Thanks for the food!) for the first time. If you were to use a print dictionary, you would first have to figure what change might have happened to "ruoasta", then add the missing -k-, to be able to find the entry "ruoka" (food). Now I know you do not use print dictionaries any more, but unfortunately your brain would have to go to these exact steps to understand the phrase, even if you know the word ruoka already.

Have a look at the changes in the table:

kk → k | tukka - tukassa Afrikka - Afrikasta
pp → p | kauppa - kaupassa Eurooppa - Euroopasta
tt → t | tyttö - tytöllä konsertti - konsertin
k → 0 | ruoka - ruoassa Turku - Turussa
uku → uvu | suku - suvussa
hke →hje | pohkeet - pohje; but: ohje - ohjeet
lke → lje | kulkea - kuljen
rke → rje | särkeä - särjen; but: purje - purjeet
nk → ng | kaupunki - kaupungit Helsinki - Helsingissä
p → v | halpa - halvat leipä - leivällä
mp → mm | ampua - ammun rumpu - rummut
t → d | pöytä - pöydällä katu - kadulla
nt → nn | ranta - rannalla Hollanti - Hollannin
lt → ll | ilta - illalla
rt → rr | kertoa - kerron parta - parran

There is no change to -hk-, -sk-, -st- and -tk, and in case the word has two consonants at the end, e.g. vapaa - vapaassa and keittiö - keittiössä.

Read more about consonant gradation in general, gradation in words, and in type 1 verbs.

Watch the following video on the subject:

https://www.youtube.com/watch?v=EAbHkPShrSg