Was probably a bit of both. Using a LL parser for NLP is an odd fit. The problem was that the n-gram parsers had a fairly large file footprint. So, paging from memory would be slow and consume battery.<p>As for tool, the Antlr3 C runtime was very fiddly. On the forums, I saw one developer give up on porting their working Antlr2 C++ runtime to Antler&#x27;s C runtime. This may have been due to C lacking exception handing, so had to implement backtracking another way. (Still, kudos to the volunteer who implemented the C runtime;  in our case, it did make it into production.)<p>For really simple NLP parsing, one hack is combine an Island parser with an LL parser. This is essentially what Siri used several years ago (have no idea what it uses now).