Ö is like the French eu.
It is very important to observe that the simple vowels are all short sounds. The corresponding long sounds are written by doubling the vowel.
Aa is a long Italian a, like the a in rather, whereas the sound of simple a is shorter than that which we (generally) give to the vowel in this word.
Ee is like the English a in pale, late.
Ii is the English ee in keen, three.
Oo is the English o in hope.
Uu is the English oo in boot.
Yy is the German ü, pronounced long.
Ää is the a in had, but long. It is a rather difficult sound, but can be obtained by lingering over the vowel of had or man, taking care not to change its quality.
Öö is the sound of the simple ö lengthened.