At 0-3 months babies are solely breast and/or bottle fed. They have oral reflexes for suckling and swallowing. It is best to feed infants at about a 45 degree angle.
At 4-6 months babies begin sucking and are no longer only suckling. The action of drinking a bottle or breast feeding is becoming less automatic and more voluntary. It is during this time period that many babies will be introduced to soft solid foods such as cereals and pureed fruits and vegetables. Cup drinking may also be introduced at this time (6 months) as they will practice their skills for future transition to the cup.
Between the ages of 6-9 months babies are able to open their mouths and wait for the spoon to enter. They are also able to use their upper lip to clean food off the spoon. At this time dissolvable soft cookies may be introduced as well as ground or lumpy solids. Many babies are able to drink from straws at 9 months.
Mashed or chopped table foods with noticeable lumps are introduced during the age range of 10-12 months. Babies also begin to take most of their liquids from a cup although bottle or breast feeding may continue for bedtime. Their tongue may protrude under the cup in order to add additional stability. At 12 months they also have a controlled, sustained bite and are able to bite through a soft cookie and possibly a harder one depending on the presence of teeth.
At 16-18 months children are given more challenging foods that require chewing such as most meats and many vegetables. By 18 months they are capable of chewing with their lips closed however they often will not, however when their lips are open they should not be losing any significant amount of food or liquid while eating and drinking.
In the 19-24 month range children will begin to gain more control of cup drinking and will bite the cup less and less. They are learning to drink in longer sequences with little to no spillage. By the age of 2 children are able to manage any type of food they like as they have learned all the skills they need to eat every type of food, although they will continue to “fine tune” these skills over the next few years.