What is the difference between Vintage fortified wine and Tawny fortified wine?

Vintage fortified is only stored in barrel for approx 18 months before bottling so it goes into bottle with more acid and fresher fruit characters it then ages in the bottle so its your decision when to drink, where as Tawny is stored in barrel for 10 years+ it oxidises and some of the acid drops out it also changes colour and has a sweeter taste.