Kazehaya is talking in a way that is technically "normal", so to speak, but he's purposely stringing together, and consequently emphasizing, the three syllables that make up "Sawako". Unfortunately, I couldn't find a way to match up the English like that, hence the notes in the tags.
...So... then...
"Sa"times like this...Um, you should...Just now...! He said her name but tried to play it off naturally!Even the prince is desperate, huh?What's up, Yano-chin?Sa... Kuronuma!There's some parts that I don't get for math. Can you teach me how to do it?S... Sure.If you're OK with me!Sweet—!These two have made almost no progress in their relationship at all, huh...Wah!
"Wa"For...
"Ko"