Language Understanding in 2 Year Old

He's doing well. When he answers that he did something he didn't do it's because young children don't remember things like an older child or adult would. They don't understand the concept of time so he probably honestly doesn't remember what he did earlier.

So, you have two ways of assessing his cognitive language recognition.

First, as you have done-- having your son verbalize answers is fine. What you described sounds very similar to most typical kids I have worked with at this age. (I led 20-30 month group for a long time). You may see that some peer girls might have more expressive language than your son-- all kids progress differently and let me say with certainty-- if they aren't developing in one area, they are certainly developing in another. Some kids aren't very verbal but show interest in other areas of toddler development, such as sorting/categorizing items, building simple structures with blocks, and exploring sensory activities. Some kids express themselves very well socially in a non-verbal manner.

From what you describe, your son seems pretty on target to me. Kids, even up to six, won't always answer every question directly or successfully or even with a 'realistic' answer (esp. as they get older and their ability to create fantasies or stories develops... some parents mistake this for lying, which is utterly different, including a different motivation.)

It might be that you should become more familiar with your child's developmental abilities for this relative age. I should note that with developmental milestones, this is a 'general' window of time where these skills are developing. Some kids will present these skills anywhere between three months ahead or three months behind or more. Here's a good link:

http://www.allthedaze.com/development3.html

I also suggest for families who worry about language comprehension/acquisition-- do limit tv and computer games; focus more on real life experiences, narrating and talking together as much as possible, and offer language with rich books and songs, etc..

Some kids are later with their emergent language and so, if you still feel at three that there is something amiss, do address it with your pediatrician. At that point, they can give you a referral to have an evaluation done and if the therapist deems it advisable, your son could receive therapy. There are early intervention programs in most areas, this would be another resource to tap into.

ETA: re-read Isn'tThisFun's post. "m not even sure that asking "What do you want for a snack?" is an appropriate question to expect an appropriate response to. Most children, at that age, still need to be given specific choices. It is just too big a question. " She is REALLY right. I often suggest that we limit any choices of food to the plate and to keep choices/questions as concrete (meaning, there is a tangible, visible option present) as possible-- little ones often don't get 'abstracts' yet.

I guess I got lost in the question somehow, but I am not really following what you mean. What are you wondering about the understanding?
Do you think he should understand more? Do you think he understands more than is typical? Do you think ____? What are you wondering?
---
What do you base the concern on? Because he makes up things to answer your questions? Because he doesn't give a longer explanation than "play in my room" or "mommy I need you!"

It's been awhile since my kids were 2 1/2, but based on the two examples you gave, he doesn't sound behind to me. Is there something else that makes you think this? Remember, a child's ability to understand something and their ability to verbalize a response to it, are not always equivalent. Kids understand language far sooner than their ability to physically form words with their mouths. But once they can form words, they don't immediately catch up in those abilities. There is still a gap between understanding and ability to verbalize.

I'm not even sure that asking "What do you want for a snack?" is an appropriate question to expect an appropriate response to. Most children, at that age, still need to be given specific choices. It is just too big a question. Think of all the foods in your refrigerator and pantry and every food you've ever introduced to him. Now you just asked your 2 1/2 year old to name one that he wants that is appropriate for a snack. It's just too big. He's likely overwhelmed with the options. Make your question smaller.
Do you prefer crackers and cheese, or apples for your snack?

When you ask "Where is Grandma?"... where is she? Is she in the next room, or is she at her house across town (or in another state)? Living in another state is rather abstract.

I also found, with my own kids, that sometimes being more cognitively developed produces problems when answering questions. Because you then have a child who understands that when grandma is out of sight, they don't really KNOW where grandma is. She could be at her house, or she might have gone out to the grocery store, or gone out in her back yard, or for a walk. So, then they don't know how to answer except to say "I don't know." Which could appear "behind" if you are simply expecting the child to respond "at her house", but actually is rather advanced, b/c they are thinking beyond the simple choices.

Did he answer the questions on the ages/stages questionnaire appropriately? Did you ask any follow up questions when he answers were vague or not what you expected?

I'm not familiar with the ages & stages questionnaire, but he sounds FINE. With those full sentences, more than fine.

For toddlers and preschoolers, there's a very blurry line between fantasy and reality. It's perfectly normal for a 2 or 3 year old to answer the question "What did you do today?" with "I turned into a rocket ship and went to the moon" because that's what he imagined doing.

And, honestly, almost no kid really likes the "What did you do today?" question. From day 1 of kindergarten, my son and have been having the following exchange:

"How was school today?"
"Fine."
"What did you do?"
"Nothing."

Really, your son's vocabulary and sentence structure sound advanced for his age. His comprehension sounds right on target. Save your worries for the teenage years :).

He's fine. Stop worrying about him being behind and enjoy him. He understands plenty and based on what you've out in the question, more than my kiddo (nearly 3) did at 2.5 ... And we did have a speech / language delay. If you are really concerned, call your local Early intervention team and have them evaluate him. He's eligible for a free eval until his 3rd birthday. But, honestly, based on the info you've provided, it would be a waste of everyone's time. They're going to use the ages and stages questionnaire too.

At that age I got 2 words together and nothing more. Often no answer. I think most kids do more than that. Just saying, kids vary.

In your example, I think i's the concept of "today" or time that they really don't understand. Today, tomorrow, this week, next month - all are abstract concepts for them right now. We kind of overcame that by talking in terms of how many "wake-ups" before a certain event. I.e., you have to wake up four more times before xmas.

He most likely understands a lot more than he is able to communicate. Complex questions ARE too complex for kids at this age. For one thing, they don't have a real concept of time. So, when you ask what he did today, he might answer with something he did last week because he doesn't really get what "today" is. My daughter just turned three and, all of a sudden, everything that happened in the past (including things that happened yesterday) were "last year." I have no idea why, but she clearly knows "last year" is in the past and has no idea how far in the past it is. : )

You have to ask more specific questions. Instead of saying "what did you do at school today," say "what games did you play at school today" or "what art projects did you make at school today." It's much easier for a child this age to answer a specific question than a general one. Most days, when my husband asks my daughter "what did you do at school today" she answers "good." But, if you ask her more specifics, she'll tell you all about the crafts, what she ate for snack, what she played outside, etc.

If he can answer the basics and he does most of what you tell him, he has normal understanding for a child his age. Even with a big vocabulary, he's not able to put the understanding and the speech together.

ETA: If you were able to answer "yes" or "sometimes" on the majority of the ASQ, then you really have nothing to worry about. Those are actually really good assessments and are the same types of questions that the pediatrician asks at well visits. Also, keep in mind that each ASQ covers a range. I think the 30 months one actually covers from 28.5 - 31.5 months, so they expect a range in ability. It's also why there are fewer ASQ's as kids get older - their rate of development changes and they learn new skills every 3 - 6 months, rather than every 2 like they do as babies.

Vocabulary
Comprehension
conversing and conversation
word acquisition
Talking
understanding of word use properly
receptive language
expressive language
communication ability
sentence structure
ALL develop at different intervals per development, and development of these communication aspects, all develop at different, age-stages.
Communication and comprehension, do not all occur nor develop at the same time, in tandem.

Your son is normal.

Kids this age, do not yet know how to have "conversation." It is still, developing.

Now, when my son was younger he had speech therapy for speech delays. However, that did NOT mean, that he was lacking in understanding at all. He understood everything... and was even advanced in many areas of development. AND his vocabulary and use of vocabulary, was advanced. He just had trouble "talking" and forming words with his mouth/tongue/throat/sound coordination. Which is why he had speech therapy.
And, once he began to speak and more clearly.... he was a non-stop talker and still is very expressive. And his use of words/vocabulary/understanding, is advanced. He understood everything, even when he was not talking.
But his talking skills, came later and speech therapy helped him.
And he is bi-lingual.

Understanding and comprehension, is not the same as talking or not.