@gpatel-fr It's really as simple as, if set to English (Canada):
Contact: +15145555555 will reliably be found by prediction once I type +151
Contact 15145554444 will not be found no matter what I type
Contact (514)555333 will not be found no matter what I type
Other contact formats (514) 555-5555, similarly won't be found. Nothing without the initial +.
Anyhow, I'm quite happy about the T9! Many thanks to you for making me aware of it, and for your help in diagnosing things. And many thanks to Lionel for creating the function!
My extensive (long-winded) testing was to try to be helpful, but I'm quite satisfied with how things function at present.
If the phone number predictions get improved for databases as mangled as mine, and various weird international standards, all the better! But sadly, I don't think I'm the person who will succeed with that.