By now you will have noticed that some Spanish words have written accent marks over one of the vowels. That mark is called el acento (ortográfico). It means that the syllable containing the accented vowel is stressed when the word is pronounced, as in the word bolígrafo (bo-Ll-gra-fo), for example.
Although all Spanish words of more than one syllable have a stressed vowel, most words do not have a written accent mark. Most words have the spoken stress exactly where native speakers of Spanish would predict it. These two simple rules tell you which syllable is accented when a word does not have a written accent.
Words that end in a vowel, –n, or –s are stressed on the next-to-last syllable.
Words that end in any other consonant are stressed on the last syllable. pro-fe-sorfe-rozco-lormu-jer
The written accent mark is used in the following situations.
A written accent mark is needed when a word does not follow the two basic rules. Look at the words in this group:
Since these words end m a vowel, –n, or –s, one would predict that they would be stressed on the next-to-last syllable. But the written accent mark shows that they are in fact accented on the last syllable.
Now look at the words in this group.
Since these words end in a consonant (other than –n or –s), one would predict that they would be stressed on the last syllable. But the written accent mark shows that they are in fact accented on the next-to-last syllable.
All words that are stressed on the third-to-last syllable must have a written accent mark. bo-lí-gra-foma-trí-cu-lama-te-má-ti-cas
When two consecutive vowels do not form a diphthong (one of the vowel is i or u), the vowel that receives the spoken stress will have a written accent mark. This pattern is very frequent in words that end in –ía.
Contrast the pronunciation of those words with the following words in which the vowels i and a do form a diphthong:
Some one-syllable words have accents to distinguish them from other words that sound like them. For example:
él (he) / el (the)tú (you) / tu (your)
sí (yes) / si (if)mí (me) / mi (my)
Interrogative and exclamatory words have a written accent on the stressed vowel. For example: