Accent rules: agudas, llanas, esdrújulas

Every Spanish word has one stressed syllable. The written accent (the tilde) appears only when that stress is not where the default rule puts it:

• Tomo un café. - I'll have a coffee. (stress on the last syllable: written)
• Mi casa es pequeña. - My house is small. (the default: nothing written)

Spanish accent rules at a glance

Count the syllables from the end of the word. The class decides whether the stressed vowel wears an accent:

• cafécoffee, an aguda
• árboltree, a llana
• músicamusic, an esdrújula

The accent is never decoration and never optional, capitals included: ÁRBOL on a sign, not ARBOL.

The vowel, n or s test

Most Spanish words end in a vowel, n or s, and most of those are stressed on the second-to-last syllable. That default is never written. Agudas and llanas are mirror images of each other:

An aguda is stressed where you would least expect it, so it is written when it ends like a default word. A llana is the default, so it is written only when it ends in some other letter:

• Es una canción muy fácil. - It's a very easy song. (aguda in n, llana in l: both written)
• No es verdad. - It isn't true. (aguda in d: nothing written)
• Mi examen es el lunes. - My exam is on Monday. (llanas in n and s: nothing written)

Esdrújulas: always accented

The default stress never reaches further back than the second-to-last syllable. So any word stressed on the third-to-last breaks the pattern and always carries an accent, with no test to run:

• El último tren es muy rápido. - The last train is very fast.
• Mi médico no contesta al teléfono. - My doctor isn't answering the phone.