This gargle is the BEST for sore throats and laryngitis (these are different diseases). If this is too much work, Gaia Herbs (an excellent source for any herbs) also makes two different excellent cough formulas for children, one for wet cough and one for dry cough.
Combine all ingredients. Gargle frequently through out the day.
You may also want to check out the quick and easy to make cough syrup or the cough and sore throat remedy. Keep in mind that using multiple remedies at the same time is fine when they are clinically sound.