Ah...I found Mavry, a native Spanish speaker from Chile, saying this in reply to a comment on the sentence "Ayer los vimos a ellos escribiendo un libro." (http://www.duolingo.com/comment/887461):
We can say "Ayer los vimos escribiendo un libro." but not "Ayer vimos a ellos escribiendo un libro."..."los" is mandatory. A ellos is correct, but redundant...you would only say a ellos for clarification when is strictly necessary or for emphasis
So what I'm thinking is that for a sentence like that one, and this one, where the direct object is a pronoun, then the direct object pronoun lo/la/los/whatever is mandatory while the clarification is not. But when the direct object is a noun, like madre or pluma, then you don't need (or maybe it's even incorrect to use) the direct object pronoun as in the sentences "Él incluye a su madre." and "Tengo una pluma."
That would be "Nosotros se lo (or la if the "it" is a feminine object) defendimos a ella"
The "to her" in that sentence is an indirect object while the "it" is a direct object. So you would have to have the indirect object "le" before the lo/la. And when you have both a "le" and a lo/la/los/las together like that, the "le" would turn into a "se". I heard it's because it's easier to say, se lo rolls off the tongue much easier than le lo. :)
I think I'm beginning to understand. So 'I see her' is 'La veo' or 'La veo a ella'. We have to use 'a' to show respect because it is a person we are talking about and not a thing. I'm still a bit confused as to why it is not 'Le veo' which would be literally 'I see to her', again conveying respect because we are talking about a person.
As you said, le veo would mean "I see to her." But we don't want the "to" in English. This isn't adding respect, it's just changing the grammar and is using the grammatically incorrect pronoun "le" instead of the grammatically correct pronoun "la." Le is an indirect object pronoun and la is a direct object pronoun, and in this sentence she is a direct object so we have to use la.
Yes, the "la" is required. I am not a Spaniard, but I have a quote from a native Spanish speaker for a different sentence but the same exact concept. The sentence was, "Ayer los vimos a ellos escribiendo un libro." In this case, the "los" serves the exact same purpose as the "la" in this sentence, and the "a ellos" serves the exact same purpose as the "a ella." (So you can just switch those in the following quote.) This is what the native Spanish speaker said:
"We can say 'Ayer los vimos escribiendo un libro.' but not 'Ayer vimos a ellos escribiendo un libro.'...'los' is mandatory. A ellos is correct, but redundant...you would only say a ellos for clarification when is strictly necessary or for emphasis"
Switching it in as if it were for this sentence...we could say:
We can say "Nosotros la podemos defender." but not ""Nosotros podemos defender a ella."..."la" is mandatory. A ella is correct, but redundant...you would only say a ella for clarification when [it] is strictly necessary or for emphasis.
No, the "la" is not directly translated to "it". The lo/la/los/las/etc. are just direct object pronouns. A direct object is something (a thing or a person) that receives the action of the verb. For example, in the sentence "I touch it." the "it" is the thing being touched, so it is a direct object. And in Spanish, you would have to put the direct object pronoun lo (if the thing is masculine) or la (if the thing is feminine) before the verb. I touch it. = Yo lo toco.
If the direct object is a person, like in the sentence "We can defend her," you still use the Spanish direct object pronoun. Because "her" is feminine, you need to use la. Also, you always have to put the Spanish object pronouns either before the verb or attached to the end of an infinitive, gerund, or participle (so you can either say "la podemos defender" or "podemos defenderla"). Again, having the la in there is just saying that a feminine object is the thing being defended (so there is a "her" that gets put after the verb in English). And the "a ella" on the end does not mean "to her". That "a" is the personal "a" and is necessary in Spanish for all objects that are people. It is not translated in English, so you might get the idea that it is a useless word, but don't think like that because it is necessary in Spanish and is very insulting to not use it. It just clarifies and emphasizes that it is an "ella" who is the direct object the "la" had been referring to: We can defend her...yes, her!
I am working on training my ear, so I'm solely listening to the prompts (not reading) whenever possible. This one has to be the most egregious example of unintelligibility so far. Even knowing what it says, she is virtually saying "nosotr la podemo défenda aire." Incorrect stresses, missing syllables. Maybe someone who's a native speaker could figure that one out without looking? I'm thinking not.