Learn Finnish: Minä valitsin painikkeen, koska ohjelmassa on virhe. - I selected the button, because there is an error in the program.

Valita is a Type 5 verb. To find its present tense stem, you drop the -ta and add -tse- to get valitse-. For the past tense, this -e- changes to an -i-, giving you the past stem valitsi-. Finally, you add the -n ending for 'I', making it valitsin.

Why does the word for button (painike) have the -n ending in painikkeen?

Painikkeen is the object of the sentence. Because selecting the button is a fully completed action, it takes the total object ending -n. Notice that for words ending in -e like painike, you add another -e- before the ending. Also, these words switch to the strong consonant grade when adding most endings, so the single k becomes a double kk.

Why is the word order ohjelmassa on virhe instead of virhe on ohjelmassa?

This is a Finnish existential sentence, which states that something exists in a particular place. In English you use 'there is', but Finnish typically starts with the location (ohjelmassa, in the program), followed by the verb (on), and ends with the thing that exists (virhe, an error).

Both painike and virhe end in -e. Do they follow the same word rules?