I am familiar with all of many assistive tools and use them regularly though I am not dyselxic, rather I have found them to be assistive tools for everything I do as a writer, from scanning in printed content, creating mindmaps, recording, uploading and transcribing interviews and notes, as well as reading back what I have written.
Similarly, all the low option assistive technologies I have and still use, from a digital recorder and a PDA that become a PSION or handheld ‘palm top’ wordprocess to the iPad and Smartphone I have today. Working with colleagues with Dyselxia I started to produce documents for them on coloured sheets.
Trackballs, footpedals and head pointers take me into a new area, though I do use a footpedal to control the playback of interviews as it makes transcription or analysis far easier. Trackballs and tablets I have used in video edit suites as alterantive and better ways to interface with the various digital asasets you are juggling. Headpointers and joysticks in this context are quite new to me, though I will be familiar with reports and documentaries on their use.
Some of the virtual screen tools are also unfamiliar, though word prediction in some sense is something many of us will have experienced with predictive text.
Speech input I have used, but clearly my context and that for a disabled user are going to be very different – my use an indulgence or supra-human tools that enhances what I can naturally acheive, whereas for a disabled person it creates access at a basic level.
Alternate keyboards like any prosphsis, unless tailored to the user, will be a compromise – it depends on the person, their needs, circumstances and resources as to whether a large keyboard for one hand keyboard will be a benefit to them.
Clearly as we start to consider tools for people with no vision or no hearing the level of sophistication and specialisation of the device increases.