A. First, you should know that very few 6-month-olds will stop an activity as exhilarating as splashing in the bath on command, regardless of how clearly the words are spoken. In fact, my own experience suggests that the more clear one is, the more likely it is that the baby will continue, if only to see your reaction. You should also know that 6-month-olds' language comprehension is still developing, so there may be times when he doesn't understand you, not because of your speech, but because of his own stage of development.
Toby has the very good fortune to grow up in a household where more than one language is used. As with any child whose parent doesn't speak the mainstream language, your child will hear words expressed differently, both by you and your husband and when he spends time with others. This won't affect Toby's comprehension -- he doesn't have a dictionary in his head of how words are supposed to be pronounced. He is just hardwired for communication, and if you say "doggie" differently than your neighbor does, he'll understand your "doggie" first. In time, his pronunciation will come to match that of his peers. You need not worry, therefore, about Toby's ability to speak clearly; it will come from exposure to those around him whose speech is more typical. (This does mean, however, that if your husband isn't able to spend as much time with your son as he'd like during the week, you should make an effort to have Toby spend time with others who use oral English, whether that means joining a playgroup or visiting other relatives.)
You should also know just how adaptable your child is. A recent study found that hearing infants whose deaf parents used sign language with them used their hands to "babble." Their hand movements were of a different frequency than those of children not exposed to sign language, and they tended to make their hand movements in the same space in front of their bodies that signs are made. This means that you can tell him "no" in oral English and you can tell him "no" in sign language as well, and he will learn to understand and express himself in both.
In addition to sign language, many deaf parents use visual cues to engage their infants' attention, such as exaggerated facial expressions. This is wonderful -- all babies benefit from experiencing multiple types of communication, from touch to sight to sound.
Your son's bilingualism is not a problem for him, it's a gift: Studies have found that hearing children from deaf families are more adaptable than most children. This may be related to their ability to switch smoothly between languages. Your deafness is also not a problem for him: Deaf parents do as good a job raising hearing children as do hearing parents, even though they often don't seem to realize it. Another recent study revealed that hearing children of deaf parents don't feel any better or worse about themselves than children of hearing parents, although deaf parents are far more critical of themselves than hearing parents.
It's understandable if you occasionally feel worried -- all parents do at times, and your deafness does present some challenges, in addition to possibly isolating you from other mothers in the community. Support exists for parents like you; in particular, you might want to contact Kids of Deaf Adults (www.koda.org), which provides information on the development of hearing children of deaf parents. Local chapters sponsor events that can offer your son the opportunity to develop a community of peers from similar families as well as his friends from the hearing world. If a chapter doesn't exist in your community, perhaps you can start one!