That is a good question. Apparently yate once uses postgresql and/or mysql to collect and hold contact information. Now, on its home page, it says "Local Address Book" but it doesn't say "implemented." And it says "Implemented" or "soon to be implemented" after every thing else, e.g. "Video - soon to be implemented.
So my answer is "no," it doesn't have a local address book. It does apparently utilize existing address books for those using google talk, facebook etc.
I am seeing a pattern: linphone says it has an address book but if used in its fully functioning form, takes a couple of hours to load. Sflphone apparently, if gtk+3 installed, uses the kde or gnome address books. Twinkle seems to be about the only one out there with a functioning local address gadget.
Of course, I am not very familiar yet with yate and may be missing something. But I doubt it. Most likely Yate, like so many programs, is cowardly.....reluctant to pass out bad news and so forces the potential user through a lot of unnecessary steps.
But thanks again for all your trying. Looks like linphone, warts and all, is probably the sip program most suitable to my needs. Too bad.