Vowel harmony

Vowel harmony is one of the most important grammar rules in Hungarian. Every time you form a Hungarian sentence, you have to deal with the rule of vowel harmony. Please, use this page as a reference in your study. It takes time and lots of practice until you feel really familiar with this rule.
Suffixes are heavily used in Hungarian language for vowels, nouns and adverbs as well. To make it harder, there are 2 or 3 versions for every suffix, for example "-ból, -ből" or "-hoz, -hez, -höz." How can we decide which one to use when? The answer is the vowel harmony. We consider 2 types of vowels - back and front. Back vowels are formed at the back of the mouth, front vowels are formed at the front of the mouth.

a - á e - é
o - ó i - í
u - ú ö - ő
ü - ű

To remember easier, use the word autó, which has 3 of the the back vowels in it. If you consider the pair of these vowels, you get all of the back vowels. Every other vowel is front vowel.
Now we consider 2 kinds of words: front and back. Front words have just front vowels in them: kenyér, hideg, felhő, zöld. Back words contain just back, or both back and front vowels: határ, rádió, könyvespolc.
Most endings have too forms, one for front and one for back words. A few endings have only one form and some endings have 3 forms.

See some form for a front word, "hideg":
hideggel, hidegben, hideghez
Now the same endings with a back word, rádió: rádióval, rádióban, rádióhoz
Study the following words with endings:
néz - nézem, lát - látom, asztal - asztalon, pohár - pohárban, tányér -tányérból

How about the 3-form endings? There are rounded and unrounded vowels among the front vowels :
Rounded: ü,ű,ö,ő and unrounded : i, i', e and é. It is important for the 3-form endings, for example "-hoz, -hez, -höz." Examples of the 3 forms are the following words:
asztal (back) szék (front unrounded) and föld (front, rounded)
These words with the above ending: asztalhoz, székhez, földhöz.
Back word receives "-hoz", front unrounded gets "-hez" and finally the front, rounded word gets "-höz."