Mine would have total meltdowns. She was always pretty high strung, not the easiest baby. Of course now knowing she has ADHD, I can see that this was probably a major contributor to the meltdowns on top of not being understood. I also think this affected her socially. It's hard to talk and play with other kids when they don't understand you. At 18 months, they generally play side by side and don't really interact the same way, but as they get older and start forming social bonds, speech issues can become a problem.
It's interesting, that speech and food issues tie in together, or tongue movements. My DD can be pretty fussy at times. She has aversions to textures, mostly breads. She can be frustrating.
With all the discussion in this thread, it's pretty easy to see how easily we can say the exact most wrong thing ever.