Sentience is such a subjective...er...subject. I mean, what exactly is "intelligence" anyway? The humans of Earth, for example, seem to be doing quite well without it. And "civilization"? That's even more of a shot in the dark. But like art and pornography, you know it when you see it—that is until some government steps in and outright bans it because certain lobbyists, influencers, or political base decide that it's way too dangerous to unleash upon the ignorant populace they wish to control or tax or get their vote or...whatever.
Sometimes, there are People involved—whether they are fleshy mammals keen on burning carbon-based fuels, or gelatinous blobs of tissues who have been able to invent hyperdrives despite a complete lack of either opposable thumbs or the desire to actually use hyperdrives to find out if they are not alone in their universe. Sometimes, there are simply very patient and deeply meditative stands of Trees with surprisingly witty senses of humor. Just ask their fungal neighbors!
The point being is that these beings are the ones most likely you can attempt to have a conversation with... or avoid, if they'd rather vaporize you or use you as a replacement fuel source to their carbon-based ones.