titansdad,
congrats on your first boxer! well, it was actually easy for us and "speak".... we had them both sit/stay, held a treat up for them to see (while staying) and told them "speak." they understood it was a command, but didn't know which one-- it did take several tries. axle was funny... he would give a silent bark, with the slobber of course! when they barked, while at sit/stay, we gave them treats and praise! for the next few days, every time we gave them a treat, we made them sit/stay, then told them speak (routine is ALWAYS a plus!). on the other hand, their mama, cherub, will NOT speak for anything! ben's mom could not get her to do it, so i was suprised when the boys did! good luck, and let me know if this helps at all!