This, That, These and Those

[Johntan]

Hi everyone,
I am currently stumbling over the Spanish words for this, that, these and those, as I'm sure many people do. I understand that ese/esa and esos/esas are that and those respectively, but it also appears that ése/ésa and ésos/ésas also mean "that" and "those". What is the difference between these? The same problem arises with este/esta & éste/ésta both meaning "this". Then there's also eso, which I'm not sure where it fits in.
Hope someone can help, any help is much appreciated.

[Rusty]

These are either adjectives or pronouns, depending on their role in the sentence.

Demonstrative Adjectives
Demonstrate the distance a noun is from the speaker (used instead of the article, which doesn't show distance)
Singular
este (m) esta (f) : this
ese (m), esa (f) : that
aquel (m), aquella (f) : that, further away
Plural
estos (m) estas (f) : these
esos (m), esas (f) : those
aquellos (m), aquellas (f) : those, further away


Demonstrative Pronouns
Replace nouns and denote the distance the noun is from the speaker
(the accent doesn't change the pronunciation, it just serves to differentiate the pronoun from the adjective)
(notice the addition of the neuter gender, used for ideas or unknown/just introduced objects)
Singular
éste (m) ésta (f), ésto (n) : this
ése (m), ésa (f), éso (n) : that
aquél (m), aquélla (f), aquéllo (n) : that, further away
Plural
éstos (m) éstas (f), éstos (n) : these
ésos (m), ésas (f), ésos (n) : those
aquéllos (m), aquéllas (f), aquéllos (n) : those, further away


This place (http://spanish.about.com/lr/spanish_demonstratives/9452/3/) may help you learn more.

[Perikles]

An excellent summary. Just to put into context if someone isn't familiar with the term demonstrative adjective or pronoun, I alway imagine that something is demonstrative if you can point a finger whilst saying it:

That man over there - demonstrative adjective describing the man you are pointing at.

What the hell is this? - demonstrative pronoun for the regurgitated breakfast on the floor you are pointing at.

Thus in Spanish
Este (adjective) chico me habló ayer - this boy (I'm pointing at) spoke to me yesterday

Éste (noun) es el chico que me habló ayer - This (person I'm pointing at) is the boy who spoke to me yesterday

And so on ...