I would say, Jane, your definition of
acento fónico is perfect. Rusty's corrections are right, but where you wrote
se cae must be said
recae.
Acento fónico is a stress of tone in the inside of the word, following this scheme:
- Agudas: _ _ ´
- Llanas: _ ´_
- Esdrújulas: ´_ _
(Where "_" is a non stressed syllable and "´" is a stressed syllable.)
This is just an acoustic point, so, you can distinguish
hablo (I speak) from
habló (I spoke).
But, you can ask why one of these words got an
acento ortográfico and the other one hasn't got it (
habló, but
háblo).
Once you know how to classify words by their
acentos fónicos, you should know when to write an
acento ortográfico over the main vowel of the stressed syllable. Here is where the
rule of vowel, n or s comes.
- Las agudas se acentúan cuando acaban en vocal, ene o ese.
- Las llanas se acentúan cuando no acaban ni en vocal, ni en ene, ni en ese.
- Las esdrújulas y sobresdrújulas se acentúan siempre.
Some examples of words clasified by their
acentos fónicos with and without
acento ortográfico:
- Agudas: camión, avión, jamás, alhelí, vendrá, pared, reloj, cartel, etc.
- Llanas: tárot, Pérez, libro, cartero, etc.
- Esdrújulas: pájaro, cántaro, esdrújula, bolígrafo, farándula, gótico, purísima, etc.
There are some other rules for dipthongs and tripthongs. Let's see them later.