Oh, Crystal. I'm so sorry that happened to you and your sister. And yes, there are complex partial seizures where you can say pretty much anything. It's a type of Temporal Lobe Epilepsy. My epi said when there is *seemingly* logical speech that it's probably coming from a seizure in the right temporal lobe.
The really stinky part of it is that you are unconcious, on autopilot, not able to direct or control your words or remember them afterwards. But to the person on the other end it sounds like a logical sentence or string of sentences, that may or may not make perfect sense. But it may also be highly inappropriate.
If you are there with the other person they may see you sit or stand, eyes open, looking perfectly awake even though you aren't. Sometimes it's hard for them to wrap their head around the fact you are having a seizure - the lights are on but nobody's home. Sometimes you can remember nothing about it, sometimes there is a faint memory, like it was a dream.
I really don't want to repeat what I've said during a seizure. But there have been a few doozies. Same with my father. He's gone now but I've talked with family members, and it seems that he had seizures too. It's sad he had all this stuff going on but was undiagnosed during his lifetime (complex and simple partials, speech, Jamais vu, etc.) My family is all taking a deep breath, because this explains a LOT about what he was going through and his (and my family's) experiences with him. And now here I am, too.
I've warned my family and friends that the day may come when I have this type of seizure with them again. What I worry about is work - I've got to be reasonably sure that the complex partials are under control before I go back, becasue if I have one there it there it would not be good.
Feel free to print out this posting and show your sister, or give her the link and have her read it. I'm sure more people will chime in, too. I"m finding here in the forum, whatever kind of seizure I have, I'm in good company with a big crowd of people just like me (and you!).