Questions & Answers about Riitelisivätkö he tästä asiasta?
Why does the verb riitelisivätkö have a 't' when the dictionary form is riidellä with a 'd'?
Riidellä (to argue) is a Type 3 verb, which means it has 'reverse' consonant gradation. The dictionary form has the weak consonant grade (d), but when we build most other forms—including the conditional—we must use the strong grade (t). This gives us the stem riitele-.
How exactly is riitelisivätkö built?
It is built piece by piece from the strong stem riitele-. First, we add the conditional marker -isi- (which drops the final e of the stem to make riitelisi-). Next, we add the 'they' ending -vät to get riitelisivät (they would argue). Finally, we attach the question ending -kö.
Why does the question ending use -kö instead of -ko?
This is because of vowel harmony. The base word riitelisivät only contains the front vowels e, i, and ä. Because of this, any attached endings must also use front vowels, so we use -kö.
Why do both tästä and asiasta end in -sta/-stä?