"The girl speaks."
Translation:Het meisje spreekt.
One would indeed expect girl to be feminine, so a de woord, in accordance with the natural gender. But all diminutives in Dutch are het woorden. The only odd thing about meisje is that the diminutive form is the common one, its 'root' de meid is used a lot less. This only the case for a few diminutives.
More on de vs het here.
'meisje' is always 'het' (because it is a diminutive and common form), 'de' is only used when the plural is given: de meisjeS (please pay attention to this end-s). I know it can be confusing, because in spoken Dutch the end-s isn't always pronounced as clear as it should be.