Here is a short follow-up to the ‘issue of pair reversal’ regarding language pairs. It seems some 90% could be achieved in this reversal process. What is lacking here is an adequate handling of disambiguation. Let us focus on one example. For it is patent in the above example, where Italian ‘venti’ is ambiguous between masculine plural noun (venti, wings) a numeral (vinti, twenty). But such specific ambiguity relating to grammatical types does not exit in French. The upshot is that disambiguation between grammatical types is specific to one given source language, at least in part. It this difficulty could be overcome, a rough 95% of the automatic process would finally be achieved.
(Obviously the current translation is not of an acceptable quality for publication: some 90% at least is in order…)
Anyway, handling sucessfully disambiguation in many languages appears to be the crux matter here. If AI could build sucessfully such disambiguation modules, it seems rule-based translation as a fast-growing ecosystem would be feasible.