Every game I make contains its own dialogue system. My favourite thing to do, which I feel is the most engaging for the player, is to highlight parts of the sentence that is being read. In one game I even experimented with those jumping letters (in Hank: Straightjacket) and I feel like it was quite fun idea. But I also got some opinions from players, that the highlights are too slow and kill the pace of the dialogue, as they can read it faster. What do you guys think? Should dialogue highlights go faster than the voiceover, or should it be close enough to the real time? Also, going back to the main topic - how can I make the dialogues more engagin outside those highlights and letter jumps?

This kind of highlighting system has two advantages:

1. It makes it easier to follow along when reading and listening to the voice acting at the same time. Helpful for illiterate players who have trouble following the text alone, hearing-impaired players who have trouble following the voice action alone, and non-native English speakers who have trouble with both. Obviously this only applies if you actually have voice acting.
2. It gives the eyes something to keep them occupied while listening to the voice acting in the absence of actual dialogue animation.

Advantage 1 is absolutely a good thing for accessibility, but more or less pointless for players who either ignore the text entirely in favor of the voice action or vice versa. Advantage 2 is weak, and should be replaced with actual animation. If you can afford voice acting, you can also afford some talking head animations.