@calinga @rambo2fit @banyaga02
The explanations about the difference in meaning given by rambo2fit and banyaga02 are correct. And banyaga02 is right about "May alam AKO". It is not "May alam KO".
Alam ko. = I know (it).
May alam ako. = (Lit: There is something I know about something/someone.) I know something (about...)."
Alam mo ba ang kantang "Pangako sa Iyo"? = Do you know the song "Pangako sa Iyo"? - Do you know how it goes/to sing it?
May alam ka ba tungkol sa kantang "Pangako sa Iyo?" = Do you have some information about the song "Pangako sa Iyo?" - Do you know the lyrics/the composer/who sang it originally/etc.?
"Alam" is actually a verb in both cases. The actual verb is "mal
aman" (to know something).
Malaman (object-focus): nal
aman, nalal
aman, malal
aman
Most often we just say this as "alam", especially in place of the present tense "nalalaman". This is like "gusto", which is actually "gustuhin" (to like something) and "ayaw", which is "inayawan" (to dislike/reject something).
Alam ko. = Nalalaman ko.
May alam ako. = May nalalaman ako.
You might be wondering how come the same verb is used with both "ko" and "ako". "Ko" would be proper since it is an object-focused verb. But why "ako"?
This would be the grammatical explanation to it. The reason has to do with the presence of "may" (there is). "May alam" is a clause by itself. It translates to "There is information/something known about something". The idea is already complete as is and the subject of the clause is the pronoun "there". It just does not say who knows the information. That's where "ako" comes in but it becomes part of a separate clause where it becomes the actor. In effect, "May alam ako" would translate to "There is something known about something and I am the one who knows it". "I am the one who knows it." = "Ako ang nakakaalam niyon". That long sentence got condensed to just "May alam ako".
May alam ako tungkol kay Mary. = There is something known about Mary and I know what it is. = There is something I know about Mary.
"Tungkol" (about) usually goes with "may alam" since it points to the subject of the information.