Thought speak is just like audible speech in several ways. <In these brackets, like Terenia said, anyone within range can hear it, regardless of whether or not they can make thought speech> Anyone can hear it, but not everyone can send it. <<Private thoughtspeak can only be heard by those it was directed to.>> So even though Iosse can't create/send/use thoughtspeak, he can hear you perfectly fine.
XD nice. EDIT: Also, I don't intend to have anyone save for the andialites/yeerks/otherthoughtspeakingbodies to hear HER thoughtspeak.. My take on it is- She's unpracticed. So thought-speaking individuals will "hear" her thinking "out loud". Humans/normal people who don't normally talk that way shouldn't hear her pro'lly, 'cause it's never been a problem BEFORE..
Again, anyone can hear it, unless you are restricting it to a smaller group or individual. I don't think that Andalites, etc, who use thought speak are more aware of/more likely to notice thoughtspeak than those who aren't..... at least, I don't think so.....
Here's hoping that helps, though I think I'm just repeating stuff...