This is the draft of a story I'm writing (I removed the descriptions):
“Sure they allow visitors?” I asked An-Mei as we headed to the pond.
“It's OK,” she said. “It's not solitary confinement, you know.”
“I admit you surprised me,” I said. “Inviting me here. After not seeing each other all this time.”
“Yeah.” An-Mei gazed at the sky with a finger under her chin. “How long had it been? Two years?”
“More or less.”
“Have I changed?”
“Not at all.”
“Neither you,” An-Mei said, inspecting me thoroughly. “You still walk the same way. Head down. Eyes on the ground. Like you've lost all purpose and meaning in life.”
“It's not that bad. I stumble upon a coin once in a while.”
An-Mei grinned. “Idiot.”
“Nice place, uh?” An-Mei said.
“Far better than in the postcards you sent me.”
“So you actually looked at them.”
“Of course. I even replied a few.”
“Uh-huh.” I counted with my fingers. “Four, I think. In the last one I asked you why you decided to join a place like this. You never answered back.”
“Oh, I didn't?”
I gave her a nod.
An-Mei stared into the pond with a grave expression on her face. Then, pursing her lips, she said, “You know, I've been thinking lately about how vast and dark the ocean is. And so full of scary, dangerous creatures. They can eat you alive, or drag you to the bottom. Anytime. When you least expect it.”
“Hey, you know,” I said, pointing to the hiking trail. “I saw someone strange on my way here."
An-Mei raised her eyes. “Someone strange?”
I nodded. “A girl. She was alone. Deep in the forest.”
“Was she staring at an ancient tree?”
“Yeah,” I said, surprised. “How did you know?”
“Be careful,” An-Mei said, ignoring my question. “No matter what, don't get close to her.”
An-Mei is more outspoken and direct. She expects people to confirm what she just said, so she often ends sentences with uh? She also uses more body language and gestures, and talks in metaphors when she's trying to hide pain.
The protagonist is more laid back, but can give quick, thoughtful answers. He's more the passive type.
As you can see both use similar words/expressions like yeah, and you know. Does this make them sound too similar? If that's the case, what can I do to make them sound more different/unique?