Yep Jasonandyawegunorts, the speech therapist has agreed that DS1 no longer has verbal dyspraxia.
We guessed about the zinc deficiency because both my boys (and I) have intolerances to various food chemicals which are commonly caused by zinc and vitamin B6 deficiency.
You can test for zinc really easily and cheaply at home with a taste test. If it tastes like water, you're really deficient; if it's so disgusting you can't help but spit it out, your levels are good. Our GP has done bloodtests for both the boys, but we had done some private testing first including a blood test for zinc & copper and our GP is quite open to slightly more 'alternative' approaches to health. Most GPs have very little training in nutrition and don't know much about testing for vitamins / minerals. (Our GP reckons I know a lot more about it all than he does - which is probably true.)
If I were going to investigate these issues from scratch, I'd do a hair minerals test which can tell you a lot about what deficiencies you might have - all you need to do is cut off a bit of hair & send off for testing. I'd look on the Magnesium Advocacy Group on Facebook for a list of practitioners who can interpret it. Ours cost about £80 for the test and Skype consultation if I remember rightly - I think many practitioners do discounts if you want more than one person tested.
I'd say it's definitely worth investigating if you have concerns. I would say that most kids I see show some symptoms of nutritional deficiencies of some kind.
DS1 was about 75% of the way to an autism diagnosis by the time he was 3, but with the right vitamin/mineral supplements and a tailored diet, he is pretty much neurotypical now. His problems with poor motor skills, fussy eating, speech problems, poor sleep, tantrums, aggression and poor social skills have pretty much all gone. My zinc deficiency had got so bad that I ended up with protein energy malnutrition (despite my diet being okay) and I got very, very ill. I wish we'd found out about nutritional issues sooner.