She's flirty online but gives one word answers on calls

Text is performance. She can craft responses, add emojis, sit with messages before replying. It's low stakes. A call is live. She can't redo her jokes or filter her voice. Some people are just less comfortable speaking on the phone, especially early on. Others are flirty in writing because writing is safer, and calls expose them. And sometimes it means she likes the idea of you more than the reality of you. One word answers don't always mean disinterest. They often just mean she's uncomfortable and hoping you'll ease off. Pay attention to whether she's still initiating texts. If she texts you but gives nothing on calls, she's staying engaged in the format she controls.

Your reply needs to do two things. First, show you noticed the difference without sounding hurt or confused. A quick line that's matter-of-fact and a bit funny takes the pressure off both of you. Second, move away from calls without abandoning the idea of voice. You can float another text exchange, suggest a different time when she might be more relaxed, or just let the conversation stay written for now. The point is to signal that you read the room and won't keep forcing something that isn't working. This builds trust more than pushing through awkwardness does.

Don't call again right after a bad call. That looks desperate and she'll brace for it. Instead, text her something normal and see if she re-engages in writing. If she does, you know the gap is specifically about voice, not about you. Wait at least a few days, then try once more if the texting stays warm. If the second call is also monosyllabic, it's time to ask directly or accept that this might not go phone-based. If she's not texting you between calls at all, she's probably not that interested. Stop trying to manufacture connection on a format she's avoiding.