In speaking Spanish, you really don’t have to worry about accents much, but in written form, they are very important. It is a part of grammar and spelling just like commas and spacing and other fun stuff are in English. The accents have two main functions. One is to tell you on which syllable to put the emphasis and the other function is to distinguish meanings on otherwise same spelling words.

Another example that demonstrates the importance of these Spanish orthographic components is the tilde ~ ‘ (both the ~ and  the ‘ are called tildes although they are somewhat different). In the case of the ~ tilde, it goes over the n to make it a separate letter of the alphabet -ñ.

With the tilde on the n the word año (pronounced anyo) it means “year” without it, the word ano means “anus”. As you can see, these little dashes and wiggle marks (diacritical marks) can make a big difference!

The placement of an accent is not by accident. There are many regular words in Spanish that have an emphasis on the second to last syllable (the penultimate). These are words like:

casa =house
mesa =table
Pablo =Pablo (Paul)
señorita =miss
computadora =computer
ojos =eyes
examen =test

All of these words must end in either s, n, or a vowel. If they do not end in s, n or a vowel, then the regular words have the emphasis on the last syllable. For example:

regular = regular
particular = private, particular
nariz =nose
normal =normal

Words whose emphasis is NOT on the second to last syllable for s, n, and vowel-ending words or whose emphasis is NOT on the last syllable for all the others are irregular and need an accent where the emphasis SHOULD go. These include:

teléfono =telephone -if it were standard it would have the emphasis on the “o” after the f since it ends in a vowel.
lápiz =pencil -if it were standard the emphasis would be on the “i” since it ends in a letter other than s, n or vowel
educación =education -if it were standard the emphasis would be on the “i”  

If you change a words by making it plural (adding an “s”) this can sometimes remove the accent. For example:

población =population
poblaciones =populations

or the opposite:
examen =test
exámenes =tests

In the first example (poblacíon) because it has become plural and there is an s, the emphasis goes to the second to last syllable which is where the emphasis should be and why there was an accent before. In the second example since it ended in an n, the stress should be on the “a” but when you make it plural it would move to the second e (the second to last syllable).

However, in this following example the accent stays because the second to last syllable would be the “i” and the emphasis needs to be on the “a”

lápiz =pencil
lápices =pencils

The other reason to add an accent has nothing to do with signaling the pronunciation emphasis/stress, but rather to specify what the word is refering to. For example:

tú versus tu –tú means “you” while tu means “your”
él versus el – él means “he” while el means “the” (for a masculine object)
sé versus se –sé means “I know” OR “Be” while  se is the reflexive part of a verb
más versus mas –más means “more” while  mas is a conjunction that means “but or although”
cómo versus como – cómo means “how” and like dónde, cuándo and other words that start a question, they have the accent whereas  como means “like” or “as”. It can also mean “I eat”. As in the joke: ¿Cómo comes? Como como como.  (How do you eat? I eat like I eat.)

For more on these common Spanish mistakes, visit this site. It is in Spanish, but is quite useful.

 This site also had some games you could play to work on your Spanish. Try the él versus el or tú versus tu ones.

Don’t worry too much about accents unless you are writing something formal, or hanging a sign or otherwise doing something that is in stone. It is kind of like writing dont instead of don’t, pry instead of probably,  thru instead of through or loose instead of lose. But as I said before in the example of año and ano it’s good to at least be aware!