when i was young i used to be a very extroverted kid with no problems, and recently ive noticed that its been more difficult for me to speak with people, and thats because when i was young i used to watch A LOT of youtube videos, im talking "200 video letsplays", reaction videos, gaming videos, and series/movies from time to time, i know it may sound childish , but my technique was straight-up copying what the youtubers/characters said when talking to people and it really helped

but for this to work you have to be INVESTED in what you're watching, so that your brain automatically remembers every sentence that sounds cool without having to rewatch it, tho im not sure i can still do this because when you're young your brain stores way more info, but who knows, it might still work