A pacifier at age 10 months is not going to affect speech (yet). However, my pediatrician recommended taking the pacifier just after weaning from the breast or bottle around age 1 because they don't have the longer term memory to keep looking for it/asking about it like they do when they are older. We took our daughter's paci around 16 months and it was no big deal. She really was only using it to sleep anyway and she was over it in a day or two. My son is 23 months old and we just took his away on Friday. We have all had some medical problems over the past year (son had a serious blood disorder, I now have cancer, etc.) so it has been harder to work on these kinds of things.....I thought he needed the extra comfort. But, since I couldn't get him to just have it at naptime and bedtime (he would run into his room and cry near his crib if I tried to leave it in there), we decided it was time to just be done with it. It has not affected his speech though, even at his age. He says tons of words and even small sentences. I think, as far as speech goes, all kids are just really different. My daughter was speaking in full sentences at 17 months old, but I don't think it had anything to do with the paci. My son never babbled either at 10 months, but he walked at 9 months old, so his pediatrician said he was using all of his energy and brain power on his motor skills, not his verbal skills. He is doing just fine now in the speech department, so it's nothing to worry about.
Bottom line, I would probably let your little one keep the paci for now and just try to use it only for sleep times (this is easier said than done, I know). At 10 months, it should only take a day or two of just leaving the paci in the bed when he gets up and it will become routine. He won't really know any different to be going and looking for it. I really wouldn't worry about the speech thing though because boys and girls especially develop at different rates in that area, so let him be a baby for a little while longer before you start worrying about him talking. :-)