Question: I read elsewhere these 3 examples Past/Completed = "Ib

Using “na” can be valid for all 3 verb aspects.If you try to translate too much you will
confuse yourself.Also there is only Aspect in Tagalog based on the action being completed, started or not or being preformed. (Also recently completed)Also whoever made these sentences didn’t put “na” there because it’s not what they wanted to say.

@PinoyTaj Thank you for your reply but it does not answer my question.The person who put the sentences together is Pobel Tree who is a Tagalog Teacher on YouTube and he specifically mentions that the 'na' word is not required in the Past/Completed sentence and that the 'na' word IS required in both the other two sentences.(I understand the use of Aspects in Tagalog but they can seldom be separated from Tense words because Tagalog uses Aspect with Tense supporting words as required and English uses Tense with Aspect supporting words as required).

@stevesmi
Hmmm I'm sure someone else can explain this better but it's basically a difference in nuance.Past/Completed = "Ibinigay ko ang leksyon kay joy"- I gave the lesson to Joy.
If you want to emphasise that you have already given the lesson to Joy, you can use "Naibigay ko na ang leksyon kay joy". Like you mentioned, na means already in this case and emphasises the action that has taken place.Present/Continuing = "Ibinibigay ko na ang leksyon kay joy"- I am giving the lesson to Joy (na is like an emphasis that at this very moment, I am giving this lesson to Joy). The alternative "Ibinibigay ko ang leksyon kay Joy" still makes sense but the nuance is more of a simple description of what you are doing. So with the addition of na, the emphasis is on "at this very moment" whereas without the na, there is no emphasis and it's just a simple description of your action. So let's say someone has been asking you when you'll give Joy the lesson for a really long time but you keep procrastinating. And finally you've decided to give Joy the lesson to get them off your back. That's when you'd use the "na" alternative to emphasise "hereee I'm giving it to her now!". The non-na alternative would be like if somebody asked you what you were up to and you just casually answer "I'm giving the lesson to Joy."Future/Contemplated = "Ibibigay ko na ang leksyon kay joy" "I will give Joy the lesson now" (this is how you'd answer if someone asked you when you'd give the lesson and you want to get across that you have the intent to give the lesson)
Ibibigay ko ang leksyon kay Joy "I will give Joy the lesson." (This is how you'd answer, for example, if someone asked you what you will do later in the day)
Again, it's just a difference in nuance. Na gives the emphasis of right now/ an emphasis of the action. Both are valid and will be understood.I hope that makes sense
Even for me, it's hard to explain haha

Please post the video and context, NA is valid in a 3 but not required in any of them.

@stevesmi I did answer your question btw…

@PinoyTaj to be fair, I think he was asking why “na” was there, and your reply didn’t have a clear answer on that point.I do like @sssalaset’s explanation as to the nuance of why the “na” is there.

@jkos He was asking why “na” is NOT there.He already explained that he understands “na” and just wants to understand why “na” isnt in the completed aspect sentence. The reason why is because the speaker doesn’t need “na” to convey what they want to say.

@PinoyTaj Gotcha…he was asking why “na” is in some places, not others. I just don’t think “because speaker did/didn’t want to” is a great answer to the question. ; ) Not trying to step on your toes here, but if the goal is a better or deeper understanding of the language he’s going to need something more than that, right?

@jkos I don’t want to start an argument over something so little but he mentioned that he understands “na” already hence my answer. The reality is that there isn’t some language secrets, or in-depth explanation as to why poble tree isn’t using “na” in the completed aspect form.Example (English)
I went to the bathroom.
I went to the bathroom already.
(Little difference just context and or preference)Tagalog example
Naligo na ako (someone asked me of I have showered yet)Naligo ako sa ulan ( someone asked me what I did today).Context is also important. As we have no context we can assume that poble tree didn’t need “na” to convey what he wanted to say.Which one you use is based on what you want to say and there is little difference between the statement just slight nuance(unless we have specific context).

@PinoyTaj Not arguing, just a civil discussion, which is good. I guess, I see so often that people “don’t know what they don’t know,” or that even though they technically know all the words in a sentence, the sentence still doesn’t make sense due to some missing piece of info or something being overlooked. OP was missing something in the translation / explanation there, that probably needed a more thorough or explicit explanation on what was going on in those sentences.

Hi Guys, To clear it up my question while not criticising, not arguing and keeping it a civil discussion...@PinoyTaj You are not correct when you say "I did answer your question…" because you replied to my question but you did not make it clear to me the point that I was querying and therefore my question was not answered to my own satisfaction.
Another of your answers says "The reason why is because the speaker doesn’t need “na” to convey what they want to say". That also does not fully answer my question because Pobel Tree says that it is NOT needed in the first sentences but IS needed in the other two sentences. So my immediate response to your reply is again WHY. Why does the speaker not need "na" in that sentence? And, continuing, why does he say it IS needed it in the other two sentences?
Asking "why" in a question and then asking why again to every reply eventually gets to the bottom line and the real reason for the action queried.
@jkos is correct in his thoughts and in his replies and thank you for trying to clear it up for me.
@sssalaset explained it well despite the difficulty. I like the answer. Thank you for a good attempt.
@AMBoy OK I will post the video link which will make my original question clearer.

Hi Guys, This is the link on YouTube
www.youtube.com/watc h?v=YfUO0956rQ8
The relevant part starts at 16 seconds into the video

@stevesmi It’s a translation lesson of the English phrase “ I gave the lesson to joy” it’s a simple phrase with no emphasis so there is no need to use “na” in the completed form . As I stated before it is simply not what the speaker intended to say or translate in this case. You can however add “na” to the other two aspects because it’s accurately compliments what the speaker is doing at that point in the action. As you stated already na can be roughly translated to now/already in English.Ibinigay ko ang leksyon kay Joy: I gave the lesson to Joy. (Completed)Ibinibigay ko na ang leksyon kay Joy: I am (Now/ or emphasis)giving the lesson to Joy . (Uncompleted)Ibibigay ko na ang leksyon kay Joy: I will (now / emphasis) give joy the lesson. (Contemplated) .You can also add “na” to the completed form if you aren’t poble tree and that’s what you want to say(aka you want to add emphasis to what you’re saying).

@PinoyTaj OK Thanks.
If I used the sentence in the the completed form and I chose to add "na", then to me it would be because the "na" translates to "already" (meaning "before") and not to add emphasis.
When you say "...it is simply not what the speaker intended to say..." I was, as jkos has cleverly understood, hoping for a "why" explanation as in some grammar rules rather than just a personal choice thing.
I've been an electronic systems engineer for many, many years and absolutely (almost) everything has to be designed and assembled following various sets of fixed rules for many different reasons but mainly safety. It seems that this is not the case in languages. It seems that translations can be inspected and made to fit certain rules but when translating the rules seem to be open to interpretation.

@stevesmi Translation is the problem here like I said before. But yes If having it mean “already” helps you understand it more than see it as that. Just know that it wont always be translatable (and make sense). The “WHY” is “Poble tree decided to translate an English sentence to Tagalog and that English sentence didn’t poses emphasis or (already in your case) so he said that “na” isn’t needed which is TRUE. However when he says “na” isn’t needed he means specifically for this translation and doesn’t mean that “na” would never work.Since this is a translation lesson my original response was even more accurate than I even intended it to be tbf.