nervousness growling

Question
Hi, I recently adopted an english mastiff.He is 9months old and was living with  2 babies,not an aggressive dog.  he seems to be nervous with  new people and sometimes my husband who is his  best friend all day but the next morning, he  growls at him.  Of course, because he is so large people are intimidated by him.   we have taken him on walks with only little stimulation such as a late walk in the park, pet co and around the  street here at home.
when visitors arrive at the house he seems happy until they talk to him. should i ask them to not speak to him or acknowledge him until he gets curious about the?  I try not to get excitable when new people come over,but some of them do. I do  have 2 keeshond dogs 4 yrs old. The curiosity has ebbed from the keeshonds, but "zues " the mastiff is becoming more comfortable in the  home now is seems obsessed with the male.Any suggestions there? I'm aware that i will need to address both of these issues separately, I'm assuming the nervousness needs to be handled first?  thanks in advance for your suggestions.
donna

Answer
Dear Donna,

You've got some big problems here.  I strongly suggest you go to http://www.apdt.com to find a qualified positive reinforcment behaviorist who can come to your home, meet you, your husband, and your dogs, and give you a comprehensive analysis of the dog and the situation and detailed instructions on how to prevent problems in your future.  I'm sorry I can't be of more help to you here but you've got some serious stuff to take care of NOW which can't be handled via email and without a lot more first-person information.

Thanks and good luck.
Suzanne Harris, BSc, CPDT
http://www.dogdaysUSA.com