My block is worsened by anxiety, but having the block is what makes me so anxious in social situations. So it's a vicious cycle. But it's not caused by anxiety alone. In situations where I'm completely relaxed, I only block on words that I'm trying to recall someone else said. It's bizarre. For example, I'll be trying to tell my husband something someone said at work, and I won't be able to get it out. But I can speak freely otherwise. It's as though I struggle when thinking about exactly what I need to say, which is probably why my block is worse in social situations, because I'm always planning exactly what to say next due to anxiety.