2 year old boy with severe articulation issues

[Guest guest]

My friend has a 2 year old son that was just diagnosed with " severe "

articulation issues. Apparently he talks a lot but is not able to say

several sounds.

Is this mercury poisoning? Is this indicative of more developmental

issues to come?

Or does this sound like just a true speech problem that can be fixed

with speech therapy? Apparently the father had some speech issues as a

young child.

Thanks