Questions & Answers about Nuori mies ajaa vanhaan linnaan.
Why does the word linna (castle) become linnaan here?
The ending shows motion towards or into a place, doing the job of the English word "to". To form it, you double the last vowel of the base word and add -n. So, linna (castle) + a + n becomes linnaan (to the castle).
Why is it vanhaan linnaan and not vanha linnaan?
In Finnish, adjectives always have to match the noun they are describing. Because linna is in the "to" form (linnaan), the adjective vanha (old) also has to take the exact same ending, becoming vanhaan.
The dictionary form for "to drive" is ajaa. Why hasn't it changed for "the man drives"?
To make the "he/she/it" form of this type of verb, you take the stem and double the last vowel. The stem for "to drive" is aja-. When you double the final -a, you get ajaa. It just happens to look exactly the same as the dictionary form!