Does anyone actually use text speeds other than 'the fastest available'? It occured to me that I didn't know any circumstance that would inspire someone to use slower speeds- and it's even a complaint to have slow speeds outside of the speedrunning community. Can anyone offer any reasons why one would opt for using slower speeds?
Not really, to be fair... I mean, the text stays until you press A anyway, so the speed at which it appears is just completely irrelevant. Maybe foreign people who aren't that good at English who want to read at the pace the text appears or something? That's the only thing I can imagine.
I can think of two situations wherein the text speed would become relevant: :: The fastest option available is not 'fast', but 'instantly' - that is, the text shows up in the box all at once. This one applies to me more (I usually have it set to 'fast'), because I have noticed, on rare occasion, that I may accidentally 'double-click' the A Button when reading text - technically it's like 1 tap that twitches fast enough it becomes 2 - so I might miss an entire section of text that would be extremely important. :: The dialogue lines have voice acting attached to them. When this happens, the text should be controlled so that it moves at roughly the same speed (or perhaps a tiny bit ahead) of the lines being spoken. It's a lot like having subtitles for movies, but it gives you the lines out for the next 2 seconds right away (a similar problem to the above 'instant text'). Some games do this really well, while others not so much - and it's really hard to give an example of a game that does this well. I do know of one, though; it's Zero Escape: Virtue's Last Reward. Almost all of the lines in cutscenes are voice-acted, and the text moves at a variable speed such that the text appearing and the voice speaking happen at roughly the same time, so it's very easy to follow along with.
I used it at a slower pace when I wanted to relax and take in the words as they hit in certain games. Usually though I do play it on max speed if I know the game or if I know the plot isn't very interesting, like in ORAS compared to XY. ORAS I had on max because it was a re-hash of the plot, while XY had a unique concept with A's story, so I played it on slow.
While text speed isn't a major aspect toward immersion, it is crucial to building a bigger audience. Most games that have text speed as an option tend to be very story driven. A few ideas I'd consider when designing any captioning or text in game would be; A slower/younger reader Voice acting Non Localized games between countries (for people who know the text as a second language) People with dyslexia and other mental disabilities and just personal preference.