This is definitely abnormal to speak only 3-4 words at 2.5 yrs
Only oral medicines won’t help a lot, although supplementing deficient micronutrients might be useful .
There is no need for any blood or urine tests unless there is any indication that there is a overall developmental delay in the child, in which case we might need it for finding a cause for the delay
Next Steps
Consultation needed for detailed examination of the child, and a more detailed history to suggest the cause of the speech delay, and also to find any other delay that might be there.
Treatment will be holistic and target all aspects, not just speech.
Health Tips
Do not ignore the speech delay and start appropriate action as soon as possible, you have already delayed evaluation and treatment by 3 months