Suggest Treatment For Speech Delay In A 2 Year Old

I have a kid of 2.5 yrs - having speech delay - we are working with him for last six months (after 2nd birth day)...has improved a lot...now in 2-word stage (connective)..... PDD was diagnosed @ 2-yrs...but after stimulation (more people at home, talking in single language rather than multi as we have shifted from our native state) has shown very good response within 2-months of attention.... At 2yrs we had lot of complains (speech, behavioral), now we have almost nothing, does good play school, mix-up with kids, plays with the, speaks of his needs (susu, potty, pani-dedo etc.)... Should we consider re-diagnose etc. as the PDD word is still within our mind...