Apparently there is no free implementation of character combining IME like Vietnamese TELEX or Chinese pinyin on Android, while the most well-known implementation for Vietnamese TELEX on desktop is freely licensed.
@huy_ngo, reject Google, return to GNU
@huy_ngo, phone call and USSD has had working GUI on phosh for several months now, and I think it's been working on Ubuntu Touch (which is your best shot for your existing phone) for a few years.
@mcsinyx Does the phone call/account refill thing work yet?