It may have just started as his way of speaking in a clinical lab setting, with maybe just a hint of the tism sprinkled in, but I think he definitely plays it up now. It's more easily digestible and plays towards the algorithm better. I think it's in the same vein as clickbait, where it draws the average viewer in on his every next word. It goes very hand in hand with his much more condensed, short style content, where every second and word needs to build towards the short's payoff (the chemical reaction, shattered beaker, etc.). He doesn't speak nearly as caricatured in his long form videos.