Using the subject pronoun ¨YO¨
Now there have been some debates about this. Some people that I have spoke with are completely against using it when not needed. Other people and also some friends that I have (all native speakers) use it all the time... Yo soy, yo vivo, yo amo, ect...
I had one man tell me that is was grammatically wrong to use it when speaking or writing, which I know is not true.
I guess its just a personal preference. What do you guys think? Are you for or against using subject pronouns when they are not needed?
10 Answers
I agree with this guy: It is not actually wrong to use it when it is not needed but no native would use it. so we can savely say: avoid its usage.
Have a look at this thread.
But I hear and see native speakers using it a lot. I have this friend to help me with my Spanish poetry writing, and when we chat, he uses it often, even when not needed.
Also in the chats, maybe about half the native speakers I chat or talk with, they use it as well.
So we cannot say that no native speaker would use it.
I find myself using "Yo" a lot (maybe too much?) and that might be because I'm not totally thinking in Spanish. And my well meaning Hispanic friends, (mostly Mexican, Puerto Rican, Ecuadorian, Spanish, Cuban, Honduran) point out the overuse. But on the other hand, these same Hispanic friends of mine use it. Maybe I just haven't figured out the subtlety of when it is appropriate (if that's the right word) to use "Yo". After all, I'm only gringo. 
I do seem to notice a change in emphasis when "Yo" is used, as shown in these two examples:
#1 "Eso es justo lo que quiero." means "That is just what I want." This makes me think the person is emphasizing "That", whatever that is. The sentence before might have been: "It's perfect! That is just what I want."
#2 "Eso es justo lo que yo quiero" still means "That is just what I want." However, now I think the person is emphasizing himself. Whatever "that" is, it is something that "He" wants. The previous sentence might be: "You have one of those? That is just what I want."
So adding the so-called 'unnecessary' "Yo" to that sentence subtly changes the idea. Of course, this is just my observation. 
Any comments?
I have seen it used in movies in this case...
Pero, yo...yo...
Like when you don't know what to say exactly...I found that use interesting.
In the movie, "The Incredibles" (English version, with the Spanish sound track activated), yo is used more than I would have thought, but I think there is a subtlety to its use I am not catching onto yet...as it certainly isn't used a lot nor every time someone needed to say "I."
The one that gets me befuddled is Usted. I often get lost when usted is the subject. Is it usted or it or what?
But, for some of the tenses, 3rd person and 1st person singular are the same...so I could see yo being used to differentiate between 1st and 3rd person as well. (Conditional tenses for example)
I am betting there are subtle cues that the Spanish-wired brain picks up on that alerts it to possible misunderstandings (due to, for example, equal conjugations) and it just automatically knows throwing in yo or usted will prevent the misunderstanding...but that same brain will have a good sense for when the yo or usted is not needed.
Just for an English comparison here...
Here in the southeastern USA, we use "they" as a gender-neutral pronoun for both singular and plural use (the verb will be plural always, but the actual person or object may be plural or singular).
If we say "I've got a guy coming here this morning." Our next sentence might be "He should be here by 9AM." BUT, if we say "I've got someone coming here this morning." Our next sentence might be "They should be here by 9AM."
It's not always so perfect, but if we introduce a person in a gender-neutral way, we are more likely to use "they" afterwards, but if we introduce them (see, because I used the gender-neutral "person" earlier) in a gender-specific way, then we are more likely to use gender-specific pronouns. But it's not something we analyze (well, I do); it just happens.
I would consider the initial introduction using a gender-specific reference (guy, girl, man, fellow) or a gender-neutral reference (person, someone, somebody) to be a "subtle cue."
But I wouldn't know Spanish's subtle cues (except maybe conjugation-confusion).
In poetry, I could see its use more, but not in everyday speach.
See, you would think so. When I write poetry and have someone proof it, they say don't use "yo" at all. Then I ask another person, and they say it's completely fine.
Then I have my friends that use "yo" in everyday speech.To me it seems about half of the people use it normally and half don't unless it's needed. Or maybe it could be a bit regional too? That usually is my answer for everything... jeje.
I've been more conscious of the use of "YO" since this question was posed and I noted the following post by Heidita in this thread.
Y no digas que está en tu perfi, es que yo no hablo inglés.
I don't want to open a new thread, since there are already some good comments here, so I am hoping that Heidita or another native speaker will see this and can help me understand why "yo" was used in this particular sentence. 
2.) "Eso es justo lo que yo quiero."
Personally I like #2 better for this sentence --- the "yo" adds the needed emphases of a strong desire.
Rules for poetry are a lot more forgiving than the usual written text. You aren't even required to use punctuation. I think for poetry you have much more latitude in your use of words.
As a matter of fact the more obscure the more I like it. I want poetry that makes me think. If you use proper wording and punctuation you might as well write a short story.
It's poetry, it's from the heart not a textbook.
That's just my thinking.
In poetry, I could see its use more, but not in everyday speach.
I think the advice to not overuse it is sound. You don't want to write a paragraph that uses it in every sentence, but I often see it used where it is non-essential in reading Spanish material. Just like you intersperse pronouns with your nouns, I think some use of the pronoun beyond emphasis or unambiguity is common and acceptable.
Myself, I'm too lazy to include any extraneous words.
I agree with this guy: It is not actually wrong to use it when it is not needed but no native would use it. so we can savely say: avoid its usage.
Have a look at this thread.
