I think that all toddlers can become easily frustrated from time to time. I know that my 27 month old son does! Overall, he is a laid back child. But since he began preschool three weeks ago, some new behaviors have arised. He has become more possessive of his toys while chanting "mine, mine!" and seems a bit more impatient, and even pinched another child after she "stole" a toy from him. How I and the staff choose to deal with these behaviors can make all of the difference in the world! I think these behaviors are normal for his age, but they should definately be redirected. Some suggestions on how to handle aggressive behavior are on the following link:
ZERO TO THREE: Aggressive Behavior
Children with developmental delays tend to get frustrated when they can't express what they want to say or when they become over-whelmed. That is when aggression may peek out in them...not because they are a bad child, but because they want what they want and when no one understands that, it can become frustrating! Many of the kids I work with become aggressive such as pushing, biting, or kicking when another child takes a toy from them. This is often because they don't yet have the ability to say "mine, mine". So, it may be frustrating that a toddler seems selfish, but it is better that they let you know they wanted that toy by saying "mine" than by pushing another child. If a teacher or other adult doesn't understand that, then the child may be wrongly punished. Although the child may need to go to time-out for hurting another child, he should also be encouraged to "use his words". I think that the suggestions in the link above mixed with suggestions by a speech language pathologist, occupational therapist, and/or developmental specialist (with ECI/EI)should help minimize the aggression in a child with developmental delay.