The letter 's' in Spanish is the center of one of the biggest phonological trends in the language. In "proper" (or at least the Castillians would say so) Spanish, the 's' always represents the fricative /s/, which is a bit more dental than the English 's' which is most definitely alveolar. Of course, this varies, and in Andalucia and most dialects of Latin American Spanish (most of them come from Andalucia), most notably the Carribean variety, the /s/ becomes /h/ or is lost entirely at the end of words. In highland dialects, such as Mexico City, Lima, or Bogotá, the 's' is always /s/, and sometimes aspiration or elision of it can be associated with the lower classes and is frowned upon. However, in Cuba, if you don't do this, you'll sound like a foreigner.
Following this rule, the words 'los pobres' will become /loh poβreh/ or /lo poβre/. Of course, this can get pretty damn confusing, since 's' hold much morphological import, such as being the only plural marker and the second-person marker in most tenses. That is to say, if 'las chicas'(the girls) and 'comes' (he eats) are pronounced /la tšika/ and /kome/, how can you tell the difference between these phrases and 'la chica' (the girl) and 'come' (he/she eats)?
The answer is that you can't, you have to tell from context. However, there is an interesting trend in Andalucia which is shaking the Romance foundations of Spanish. This trend is the opening of vowels where the 's' disappears. In this way 'los pobres' becomes 'lc pcβrε' (I use 'c' to represent the open 'o' since I can't seem to adequately find this symbol in Unicode, which is a backwards 'c'), las chicas becomes 'lə chIkə', and 'comes' becomes 'kcmε'.
This, of course, flies in the face of Romance and modern Germanic plural-forming, which is usually a change at the end of the word, whether it be 'i' 's' 'en' 'ar' 'eux' or whatever. It's more like the goose/geese, Bruder/Brüder distinction in the older nouns of English and German, or like the consonantal Semitic languages like Arabic and Hebrew. Most importantly, it messes with the 5-vowel system of Spanish, in which the open vowels /ə/, /ε/, /I/, /c/, /U are allophones of /a/, /e/, /i/, /o/, /u/, respectively. If this trend, which mainly occurs in parts of Andalucia, were to continue unchecked, it would give Spanish a system of at least 10 phonemic vowels. This kind of stuff is the content of a linguist's wet dream.
A guide to phonetic symbols used for English speakers:
- /s/...like in English, but with the tip of the tongue more towards the back of the teeth
- /h/...like in English
- /p/...the English 'p' is usually pronounced with a puff of air, as in 'pop'. Spanish does not have this, and to an English speaker it will sound like 'b' at first
- /β/ Basically, this sound is somewhere between English 'v' in 'cove' and 'w' in 'cower'. This is what happens to /b/ when it comes in the middle of a word.
- /r/...NOT the English 'r', but more like the 't' in 'water' or the 'd' in 'udder' in many dialects. It's kind of like a very quick 'd', and is called a tap or flap.
- /tš/...Like the English 'ch' in 'cheese', but withoutthe puff of air (see /p/)
- /k/...like in English 'cat', but without the puff of air (see /p/)
- /m/...just like in English 'mom'.
- /a/...like 'father' or 'hot'
- /e/...like 'fate' or 'weigh', but without the 'y' sound English tends to put at the end of it
- /i/...like 'be' or 'seat', but without the 'y' sound (see /e/)
- /o/...like 'hope' and 'soak', but without the 'w' sound English tends to end it with.
- /u/...like 'sue' or 'loot', but without the 'w' sound (see /o/)
- /ə/...the 'schwa' like 'banana', 'carrot', 'heaven', etc. A very, very common sound in English
- /ε/...like 'bet' or 'ember'
- /I/...like 'bit', 'ill'
- /c/ (actual IPA is backwards c)...like 'walk', 'paw', or 'taut' in some dialects of English (namely, New York, New Jersey, New Orleans)
- /U/...like 'book' or 'put'
for more info on all this, see my writeup under How to pronounce Spanish