They are pronouns attached to the verbs, in order to specify the object that receives the action (I, you, he/she, they). It works in the same way as English pronouns "me, you, him, her, them". Examples: verbo ajudar (verb to help) - Imperative singular form: ajude (help!) Ajude-me = Help me! Ajude-te = Help you! (help yourself) Ajude-o = Help him! Ajude-a = Help her! Ajude-nos = Help us! Ajudai-vos = Help you! (help yourselves) Ajude-os = Help them! (masculine form) Ajude-as = Help them! (feminine form) verbo ajudar (verb to help) - Infinitive form Ajudar-me = To help me Ajudar-te = To help you (singular) Ajudá-lo = To help him Ajudá-la= To help her Ajudar-nos = To help us Ajudar-vos = To help you (plural) Ajudá-los = To help them (masculine form) Ajudá-las = To help them (feminine form) Note that "-la, -lo, -las, -los" are used only in infinitive forms and in the cases you use mesóclises ("ajudá-lo-ei" - I'll help him). However, I don't recommend you to try the mesóclises since they are hard to learn and are not used in our daily communication (not even in formal or scholar situations). When you use them, notice that you'll drop the "ar, er, ir" infinitive endings, replacing them by "á, ê, i". Comer - comê-lo Amar - amá-lo Cobrir - cobri-lo

Ok, now let's see when to use LO or LA or LOS or LAS with some examples: 1) I am going to open the door. I am going to open it. Eu vou abrir a porta. Eu vou ABRÍ-LA. porta (door) is in sigular form and is a feminine noun (PS: in portuguese there is no neutral noun), so you have to use LA (sigular/feminine). 2) I am going to open the presents. I am going to open them. Eu vou abrir os presentes. Eu vou ABRÍ-LOS. presentes (presents) is in plural form and is a masculine noun, so you have to use LOS (plural/masculine). 3) I have to thank the girls. I have to thank them. Eu tenho que agradecer às meninas. Eu tenho que AGRADECÊ-LAS. meninas (girls) is in plural form and is a feminine noun, so you have to use LAS (plural/feminine). 4) I want to see you. Eu quero te ver. Do you remember "you=te" ? By the way, unlike english, most of time we use the pronoun before the verb: "te ver" instead of "ver te". Except in the cases when we have to use "lo, la, los, las", as we have seen before: abrí-lo. If you are talking or writing to a friend (I mean if it's a very informal situation) you don't have to use all these rules. If you wanna know how to simplify and speak in a colloquial way, send me a message, I guess I kinda have written a lot already. =P

As Uedden Luiz said, they are not very used in spoken language, but you do use it when you are writing something more formal (like an e-mail to a boss, for example). The pronouns you asked about usually refer to something already mentioned in a sentence or piece of text. They are used instead of nouns to prevent repetition of the noun to which they refer. me = me you = te him/her = o/a it = o/a (you have to know the gender of the word you are referring to) us = nos them = os/as (you have to know the gender of the word you are referring to) "o", "a", "os", "as" you have to use together with the letter "L" (lo,la,los,las) if the verb of the sentence is in the infinitive. Examples: 1) I'm helping him = Eu o estou ajudando (the verb "help" is not in the present continuous, not in the infinitive, so you DON'T use the "L" together with the "o" in order to refer to "HIM"). 2) I would like to help him = Eu gostaria de ajudá-lo (the verb "help" is in its infinitive form (which means it's not conjugated) so we use the particle "LO". The verb that is actually conjugated in this sentence is the verb "like" cause we said "I would like"). One more thing. Everytime you use the particles LO,LA, LOS,LAS, you have to: 1) remove the final R from the verb (PS: every verb in its infinitive form ends with the letter R) 2) add an accent to the final vowel (PS: if the final vowel is "i" or "a" you use "í" or "á" and if it's "e" you use "ê" - remember that every portuguese verb in its infinitive form ends with "AR", "ER" or "IR") 3) use "-" between the verb and the particle. Example: Verb in the infinitive form => verb with the particle AJUDAR (help) => AJUDÁ-LO, AJUDÁ-LA, AJUDÁ-LOS, AJUDÁ-LAS ABRIR (open) => ABRÍ-LO, ABRÍ-LA, ABRÍ-LOS, ABRÍ-LAS COMER (eat) =>COMÊ-LO, COMÊ-LA, COMÊ-LOS, COMÊ-LAS

Aqui no Brasil usamos muito pouco essa particulas -lo -la e -se, quando estamos conversando. Quando estamos escrevendo aí somos obrigrados a usar (ou, usa-las), mas ficamos com dúvidas se está correto. Agora eu acredito que só as usamos nos verbos. Vou te dar uns exemplos: Vou guardar o livro = Vou guarda-lo. Vou guardar a faca = Vou guarda-la. As pessoas matam por dinheiro =~ Mata-se por dinheiro. Veja a gramatica em: Particula -se: http://www.brasilescola.com/gramatica/funcoes-particula-se.htm Particulas -lo, -la (Pronomes oblíquos) http://www.portugues.com.br/morfologia/classes/pronome/cpessoais.asp Qualquer dúvida pode me perguntar em português, inglês ou espanhol.

LO-LA-LOS-LAS replace the direct object when mentioned a second time. They will happen if the verb ends in R,S,Z. If the verb ends in M,ĀO, ÕE we have to replace the direct object by NO-NA-NOS-NAS. If someones says: Anali morreu - even if we don't know who Anali is we understand the sentence. When the sentence has its full meaning up to the verb we call this verb intransitive, in other words, it doesn't need a complement. If someone says: Eu comprei (bought) our natural question will be O QUE= what. The answer to the question O QUE = what is our direct object. Eu comprei um carro ( I bought a car) and our verb is called VTD = verbo transitivo direto. (Direct Transitive Verb) and the complement of this verb is the Direct Object = Objeto direto. As in the phrase: Eu comprei um carro our verb doesnt end in 'R,S,Z or M, AO OE then we can not replace the direct object by LO, LA, LOS, LAS, NO, NA, NOS, NAS, but we can replace it by O,A,OS, AS and in this case we can place it before or after the verb. Eu comprei um carro. Eu o comprei ontem OR Eu comprei-o ontem (I bought a car. I bought IT yesterday. If I change the sentence to; EU VOU COMPRAR UM CARRO = Eu vou comprá-lo NOS COMPRAMOS ROUPA= Compramo-las ELA FAZ BOLOS= Ela fá-los (this is not used in Brazil in spoken or written language, only in Portugal) Eles compram casas = Compram-nas Elas dão esmolas - dão-nas Põe seu casaco = Põe-no agora. As you could see above if the DO (direct object) is replaced by lo,la,los, las the verb loses the last letter R_S_Z and receive an accent. If it ends in m, ão, õe it doesnt lose the last letter. I hope this makes sense and help someone. The other pronouns ME-TE-SE-LHE-NOS-LHE replace the INDIRECT OBJECT Edinaldo http://london-portugueselessons.co.uk