tp offers a range of possibilities for other than alphabetic writing systems and other than oral face to face communications. To begin with the obvious. the restricted set of syllables, so nicely laid out in a grid, suggests a syllabary -- starting with Japanese (complete with the -n marker) and then going on to others satisfying various aesthetics. Equally obvious, the fact that there are only 123 words (count on 09/10/17) makes it natural for a picto-/ideo-/logo- graphic system, ala Chinese -- perhaps with a syllabic or alphabetic side system to cover the unofficial proper adjectives. And again, aesthetics sets various criteria for these: how much ideo and how much phono for starters, then what ideos are clearest and so on. This same feature encourages a sign language (or several) since there is an easily learned set of signs (plus finger spelling, of course) and, again, there is the issue of what best represents the words involved (again ideo v phono in part): borrowing from any of the recognized SLs (including Iron Eyes Cody's or some one else's version of Plains Indian) or creatio de novo for this new language. In addition (is this on Sonja's list?), there is the question of secret tp although, with only 123 word (today) things like Pig Latin and Alfalfa aren't going to be very concealing (not that those work very well), but hashbash has some promise, as does something like Emrys and Fink's hand-holding pressure code (a bit spelling centered but probably adaptable).
Now, I am perfectly happy with the Latin alphabet, but tp is simple enough to learn that the additional effort of a new orthography or dactylography doesn't seem out of the question. Go to it!