If it's the only thing spoken at home (by you and your spouse) the kid won't have much of a choice; he'll learn to speak Latin.
A Russian-speaking friend of mine told me that when he was a kid he didn't always want to speak Russian because no one else did, but when he was at home his parents would ignore him when he tried to use English, even though they understood him. He speaks Russian fluently now.
Compare this to my grandmother's attempts at speaking French with her children: My grandmother spoke French with my aunt (their first child), but my grandfather didn't speak it and spoke English with her. Eventually my aunt decided she would only speak English, and when my grandmother tried to get her to speak French she would run to my grandfather and get what she wanted that way. They couldn't enforce any sort of French-only because my grandfather needed to speak English, so my aunt eventually stopped speaking it and the younger children followed suit.
Alternately, have twins and expound the virtues of secret twin languages every chance you get (in Latin, of course
Native: [flag=]en-ca[/flag] Pretty Good: [flag=]fr[/flag] [flag=]la[/flag] Just Started: [flag=]de[/flag] Interested: [flag=]en_old[/flag] [flag=]akk[/flag] [flag=]grc[/flag] [flag=]he-hbo[/flag] [flag=]egy[/flag]
Learn all the dead languages!