Earlier quoted context omitted.
For what it's worth, this is basically just the same as any popular Japanese (or Chinese) input method. Usually the approach is to greedily form the smallest set of the longest words from the given syllables, because people tend to give inputs where all the words are complete. Sometimes people use markov models to fix situations where that falls over. Not sure how well this model performs, but the task is not novel.…
Spoken Japanese isn't any more ambiguous than English (for a human, or a speech-to-text AI) because Japanese people pause between spoken words just like anyone else. But a stream of romaji furigana with no spaces is quite ambiguous—since there's nothing to indicate word boundaries, any substring of the input might turn out to have actually intended to be e.g. a katakana spelling of a name. If CJK IMEs expected and re…
Also intonation, which is not captured by the written system at all. Japanese isn't strongly tonal in the way Chinese is, but it has a regional prosody, like Swedish, which helps in disambiguating meaning.