My son was just a little over one year old. He was used to being latched to me, having me always right there next to him. I was lying down with him while he was napping, but got up to do something in the living room. Â He woke up without me right there, and he was furious!
I came to him, held him, and listened to his feelings for about 45 minutes, until he felt better. Immediately after that, he said his first sentence! Until then, he had been putting at most two words together.  He said very clearly, “That's a big red truck.” This was directly after crying for 45 minutes. He cried hard, he came out of it a completely calm child, and then, out came this perfect sentence!  To me, this is proof that crying helped his mind make a big leap in language skill.
 — A mom in San Bruno, California