AGUDAS
We call agudas those words in which the last syllable is the tónica. They have the stress on the last syllable.
caracol
verdad
camión
instructor
corazón
pintor.
Words that are agudas carry a tilde (accent mark) when they end in -n, -s or a vowel.
comió
canción
café
balón
Tomás
** Words that are agudas and come from other languages like English, that end in – s but this one is preceded by a consonant, do not carry a tilde.
Also, words that are agudas and end in -y do not carry a tilde, as y is a consonant.
LLANAS
We call llanas those words in which the stress falls in the next to the last syllable.
lápiz
toro
come
carta
hábil.
Words that are llanas carry a tilde if they do not end in -n, -s or a vowel.
lápiz
cáliz
hábil
Words that are llanas also carry an accent mark or tilde when they end in -s preceded by another consonant.
bíceps
cómics
ESDRÚJULAS
These are words that carry the stress or the strength in the third syllable (we always count from the last syllable backwards).
teléfono
esdrújula
tarántula
espátula
cómpralas
Words that are esdrújulas always carry an accent mark. This makes it easy, doesn´t it?
mecánico
cántico
cántaro
esdrújula
brújula
These are words in which the stress falls in the fourth or higher syllables.
cómetelas
alfabéticamente
inútilmente
cómpraselas