These words are often adjectives, but can also be pronouns and even adverbs, and are used to identify people or things of indefinite or unknown rather than specific quantities.

Many of these words change gender and quantity, such as the Spanish translation for the word "some".

algún café		some coffee	alguna mujer		some woman
algunos regalos		some gifts	algunas casas		some houses

Some other Spanish Indefinite Words

algo - something
alguien - someone
bastante - plenty of, enough
cada - each, every
cualquiera - any, anybody, anyone
demasiado - too much
mucho - a lot
nada - nothing, not at all
nadie - noone
ni siquiera - not even
ninguno/ninguna - nobody, nothing, none, not any
otro - other, another
poco - little, not much
todo el mundo - everybody (literally "the whole world")
un poco - a little bit
uno(s) una(s) - one, some
unos cuantos/unas cuantas - a few, some, several
varios/ varias - several, various

Tengo bastante trabajo en mi casa. 
I have plenty of work to do in my house.

Hablo un poco de ingles. 
I speak a little English.

Somos de varios países
We are from various countries

El sol está demasiado fuerte hoy - me voy a quemar
The sun is too strong today, I'm going to get sunburned