What could be the reasons why people have to think of what they say when havng conversation?

Question

when before they are very spontaneous and loves talking

Answer 1

If something is bothering you and isn't being dealt with it can cause difficulties with speaking and writing. It might feel like you're trying to say two or more things at once. Like all your thoughts have come to a bottleneck and are struggling to get out, but only they're stuck. The best way to deal with it is to find what's bothering you and work through it one step at a time.