Yesterday, I had a phone call from a friend who has a son just a few days younger than my 9-month-old. She's a Speech-Language Pathologist as well and she was getting worried that her baby wasn't yet babbling with consonants (eg. bababa, mamama). The P, B, and M sounds tend to be the earliest sounds that babies say because they are relatively easy to say (baby just has to put his lips together and vocalize). All babies develop at their own rate, but we still expect them to achieve milestones at a certain time. Even at such a young age, identifying issues can help avoid a delay or allow access to support early to reduce the effects of a delay.
My friend's baby was quite vocal - making lots of vowel sounds and gurgles - but he wasn't doing much movement with his lips yet. This can be an indication of some trouble with oral motor movements to produce speech. We discussed the possibility of oral motor issues but her son didn't have any other indicators of this - he wasn't a messy eater and he could imitate blowing raspberries and do other oral movements easily. My friend decided that she and her family would continue to give her son good models of babbling and encourage all his verbal attempts with the hope that he would start to catch on to babbling soon in order to move on to the next stage of language development - real words!