Where does stress fall in Spanish words and how are exceptions marked?

• A. Stress falls on the penultimate syllable if the word ends in a vowel, n, or s; otherwise on the last syllable. Written accents mark exceptions (árbol; canción).
• B. Stress falls on the final syllable for all words; accents mark exceptions.
• C. Stress falls on the first syllable for all words; no exceptions.
• D. Accents are not used to mark stress; only to indicate question.

Answer: (A)

In Spanish, where a word is stressed is predictable from how the word ends. If a word ends in a vowel, or in the consonants n or s, the natural stress falls on the penultimate syllable (the one right before the last). If a word ends in any other consonant, the stress falls on the last syllable. When the pronunciation would violate this rule, an accent mark (tilde) is used on the stressed vowel to show where the stress should fall.

Those accent marks are what signal exceptions. For example, árbol ends with l, so without any marks you’d expect the stress on the last syllable. The written accent on á tells us the stress is actually on the first syllable, an exception to the ending rule. Canción ends with n, so the default would be on the penultimate syllable, but the accent on ó shows the stress shifts to the final syllable.

So the best description is that stress follows the ending rule, and written accents mark deviations from that rule. Some other statements try to claim stress is always on a single fixed syllable or that accents aren’t used for this purpose, which doesn’t fit the variety seen in actual Spanish words.