That is indeed a fairly sizable gap. A language-based learning disability is one of the possible interpretations/explanations. But not the only one. Do you see any indication IRL that she is stronger in visual-spatial, quantitative, or abstract problem-solving areas than she is in verbal areas? Or any sign that she is not as skilled in expressing herself verbally, or comprehending complex language? It's probably worth keeping an eye on, but not necessarily panicking over, unless you have other concerns, independent of the test score (of course, even then, no actual need to panic!).
