These are called object pronouns and they take a little practice. Though don't worry, object pronouns are basically just words that mean 'it' or 'him or her'.
To break it down simply:
'Lo' = 'it' for masculine nouns and is also the word for 'him'.
'La' = 'it' for feminine nouns and is also the word for 'her'.
'Le' = this is called the indirect object pronoun, we'll talk more about that later.
For example, let's take a book. In Spanish, this noun is masculine - 'el libro'.
- If you want to say that you're reading it, you can simply say 'lo leo.'
- If you're referring to a man, and you want to say that you can see him, you can just say 'lo veo.'
Tip! Put the pronoun just before the verb and you can't go wrong.
Now, 'le' is trickier. It refers to what's called indirect objects, which is when you have more than one object in a sentence.
For example, take the sentence: "I sing him a song.' The song and the man are both objects in the sentence. The indirect object is the one receiving the action.
You can always figure out what the indirect object is by putting 'to' in front of whichever one seems most correct.
E.g. "le canto una canción." Or, "I sing a song to him."
You can also use 'le' as an indirect object pronoun for both genders.
"To him" and "to her" are the same in Spanish, but 'le' can also mean just 'him'.
So you can say: "le canto una canción" and it's not clear whether you're referring to a man or a woman.
"Le veo" is a sentence that shows you must be talking about a man.
Remember! For sentences with only one object, 'le' and 'lo' can do the same thing, but 'la' can only refer to women.
Lastly, when you have an indirect object 'le' often changes to 'se'. Let's take the previous sentence as an example - you know that "I sing him/her a song" is "le canto una canción."
But what happens if you want to say "I sing it to him/her"? Then the 'le' changes to 'se' for phonetic reasons.
For example:
"La canto" = "I sing it"
This becomes...
"Se la canto" = "I sing it to him/her"
This is the trickiest thing about object pronouns in Spanish. Never say "le lo" together in one sentence, and to make everything sounds that little bit nicer - it always becomes "se lo."
If you ever see "le lo/la" in sentence then you know you've made a mistake!