OK, I figured it out. I made a kind of step manager that counts steps and authorizes the typewriter to go when necessary delta_time relative value is reached. It is not perfect, because it can work with whole numbers only, but it's overall OK at least for 60-144 FPS setups. For lower framerate it slows down, hélas. Now I need something similar to adapt portrait and mouth animations and I'm kinda stuck with it. Whatever I do, the animation is too fast like if it is not related to my delta_time multipliers at all T_T