LA TILDE (=The written stress accent) A1

THE ACCENT
Few cases: A `diéresis´(diaresis) is used (e.g. ü)
Apart from those cases there is only one accent in Spanish (á).

Accent is used only in this situations:
* To show that a word does not follow the general rules
* To eliminate confusion between words wich are spelt thesame;
* In interrogatives and exclamations.

RULES OF NATURAL STRESS
If a word ends in and -n, -s or a vowel the stress falls on the last but one syllable:
ventaja  (advantage)
maletas (suitcase)
andan (they walk)
So they are called `LLANAS´

If a word ends in any other sound the stress goes naturally on the last syllable:
nariz (nose)
español (Spanish)
They are called `AGUDAS´

And the rule now is only the words that violent the natural rule are stressed, so the accent is used when they dont follow the natural rules.   Then a stress mark must be put on the vowel.
árbol  (tree)
inglés (English)

So, here we have how we understand this in Spanish:
1st rule: `agudas´ ending in vowel, -n or -s.
  Las palabras AGUDAS terminadas en vocal y las consonantes `n´ y `s´
    Café, compás, león, iglú

2nd rule: `llanas´ ending in a consonant
    Las palabras LLANAS terminadas en consonante (excepto `n´ y  `s´).
    árbol
    mártir

3º Every pronunciation of syllables before the first or the second place are always stressed:
    The are called `ESDRÚJULAS´
    héroe
    élite
   
Or even in the previous syllables, then they are called `sobresdrújulas´

Antoher use for the stress marks is when they are needed to differentiate between two words that are spelt and pronunced the same way:
el (the) and él (he)
si (if) and sí (yes)
tu (your) and tú (you)

Interrogatives and negatives are needed to stress marks in certain circumstances. And also exclamations, see:
¿Qué?       What?
¿Cuándo?  When?