Most parents are often not sure whether or when to become concerned about their child’s speech, language or sensori-motor development. Here are some guidelines to follow.
Possible “Red Flags”
“Typical” development is a difficult concept to define at any age, but it can be particularly complex for children under age five. During these early years, children are developing new skills in a number of areas simultaneously. Occasionally development in one area may lag behind or even regress a bit, leaving parents wondering whether to worry. 
When screening young children, we are looking for “red flags” and recommend further assessment if we find areas of concern such as the following:
Age 2-3:
Language: Not steadily progressing from the single word level through to the emergent sentence level (3-5 words).
Speech: Able to be understood less than 70% of the time, numerous sound errors/substitutions/distortions.
Sensory: Withdraws or protests when touched without warning or when introduced to novel textures, movement activities, and/or foods.
Motor: Not progressing from independent walking to running (not just fast walk)
Age 3-4:
Language: Not yet beginning to tell simple stories, numerous grammatical errors, difficulty using language during peer interactions.
Speech: Able to be understood less than 80% of the time, numerous sound errors/substitutions/distortions.
Sensory: Avoids playing with other children, showing particular difficulty in groups.
Motor: Not progressing from both feet on each stair to one foot per stair.
Age 4-5:
Language: Difficulty putting thoughts into words fluently, numerous grammatical errors, difficulty engaging in reciprocal conversation with peers.
Speech: Able to be understood less than 90% of the time, sound substitutions evident (using one sound in place of another, e.g., “t” for “k”), distortion of a number of sounds.
Sensory: Becomes overwhelmed by sensory stimulation responding with caution or defiance; is under-sensitive to sensory stimulation becoming withdrawn and difficult to engage; is disorganized resulting in impulsivity.
Motor: Not progressing to being able to balance on one foot for more than 5 seconds.
If you find that your child is behind in these areas, you may want to see a child psychologist for developmental screening.