Umlauts and accents are two different stories.
Umlauts are actually different vowels, so they are really pronounced differently. lauten sounds different from läuten.
The accent in Spanish serves two different purposes. Number one is to mark a derivation from the default pronounciation rule as already explained by @hiptothehop . Note that there is often some regularity to be found here. For example, words that end with ~ción, which is the way words are nomalized in Spanish. Examples are relación, distribución, consideración. As you can see, they all share the same placement of the accent, as their ending is pronounced the same.
Another possible reason is to differentiate monosyllable words that are pronounced identical but have different meaning, like el vs él. The first is the masculine definite article the, the second is the masculine personal pronoun he.
Note that ñ has no accent, it is a differently pronounced consonant, similar to the German umlauts.
If a language has several accents, they pronounciation should differ, but I never learned such a language so someone else has to add more precise information here.
Hope that helps.