- First introduction: "So you're ___. Hello. My name is Isaac. I look after the windmills in town. It's very nice to meet you."
- Morning: "Good morning, ____. You're looking well today."
- Evening: "Oh, ___. Good evening. I hope you're not working this late!"
- At the cafe: "The tea here is fantastic. Take a seat and have a cup!"
- At home: "Ahh. There's really no place like home."
- At the mayor's home: "The mayor listens to everyone's concerns. It's good to know that our town is in such good hands."
- "Windmills are amazing machines. Harnessing the power of the wind..."
- "Windmills require a lot of maintenence. I care for each one like it's one of my children!"
- "Every single gear in a windmill is important. If one breaks, the whole thing grinds to a halt."
- "I love this town. I've lived here all my life."
- After a storm: "Phew. That was some bad weather. But you can mill things much faster in storms like that."
- Bazaar day: "There's a bazaar today! I hope we get a lot of business."
- At the bazaar: "I've been to more bazaars here than I can count. I can strike a pretty hard bargain."
- After the bazaar: "How was business today? Did you do well?"
- When shown the Blue Feather: "A Blue Feather? Haven't seen one of those in awhile."
- After you're married: "You look different since your marriage. Like you've grown up a little."
- Favorite: "Ho ho ho. I really love Jelly Bread. Thank you very much!"
- Loved: "Oh, is this for me? Oh, how nice. Thank you very much."
- Liked: "Ho ho ho. Thank you."
- Disliked: "Ah... I don't like these..."
- Horror: "Wow, it's the thing that I hate most in the world. Are you trying to make me mad?"
- You try to give a tool/rotten item: "You should really hold onto that."
- When offered multiple gifts: "I couldn't possibly accept another gift today."
Note: Isaac's heart lines can be seen by talking to him upstairs in his home.
- Black Heart: "Being a farmer seems like it's hard work. How do you find enough time in the day to get everything done?"
- Purple Heart: "Wilbur and I have been friends since childhood. Our families get along really well too."
- Blue Heart: "Not many people are using the windmills. I'm glad you came to this town, ____!"
- Green Heart: "The meals that Nellie makes are very good, but... she always makes so much! And look at me now! Ho ho ho ho."
- Yellow Heart: "Wilbur built this house for Nellie and me. He really made a sturdy and wonderful home."
- Orange Heart: "This town has always had windmills. I've improved them a bit in my time, though."
- Red Heart: "How are things going? Let me know if you ever need a hand with anything."
- Before a festival starts: "It's going to be a great festival today!"
- You lose: "Better luck next time."
- You win: "Ho ho ho. Congratulations!"
- You don't enter/compete: "Oh, you didn't enter? Too busy?"
- "I hope you've been stocking up on flowers to give!"
- When given a flower: "What a nice flower. Thank you very much."
- "That was delicious!"