Darius is 18 months of age. His mother, Mrs. Bluestone, has referred him for a speech evaluation because he says "wike" for "like" and has difficulty with consonant blends such as the str in "street." What common mistake has Darius's mother made?
◦ She did not listen to enough speech sounds before referring him.
◦ She should have tried to assist Darius herself before referring him.
◦ She is confusing typical development with articulation errors.
◦ She did not observe him in a variety of settings to see if he had similar problems.