Definitely normal. My daughter was speakiing in full sentences by 18 months, but my son is just now starting to put 2 words together at 27 months and has recently had a language explosion as well! The 2 others in my care are both 25 months (and boys) and one is ahead of my son language wise, but not by far, and the other has a short list of about 10 single words that you can barely understand. The last one was tested and was still found to be in the normal range and expected to take off in a few months. I, too, encourage them to use their words instead of grunting and whining