The Markers SA and KAY/KINA

A. SA
There is one more set of markers that goes with nouns: SA and KAY/KINA. The marker SA has many different meanings. In the most general sense, SA is a marker that deals withdirection and location. It covers the meaning of most prepositions in English.
If we break down the word preposition, we see it is made up of the Latin based component pre which means "before", and position which means "position". So a preposition is a word that is positioned before another word (its like a marker).  

For example, in the sentence 

Go to the house,

to is a preposition. In English grammar, it is often said that a preposition is anything that a squirrel can do to a tree (it can go through the tree, around the tree, up the tree, down the tree, etc.). Well, in Tagalog, instead of having a whole lot of different prepositions they just have one: SA. The marker SA is a very broad word that is used anytime the speaker is talking about the location or direction of something. The exact meaning of SA depends on the context. 
It is important to note that, like NG, the words marked by SA are not in focus.
Functions of the maker SA
1. SA marks location. Most prepositional phrases in English indicating some location are expressed in Tagalog as SA-phrases. Below are some examples:

May party sa bahay ko sa Sabado.	There's going to be a party at my house      on Saturday.
Nakatira ako sa San Juan Village.	I live in San Juan Village.
Nag-aaral si Maya sa Unibersidad ng     Pilipinas.	Maya studies at the University of       the Philippines.
Nagluluto ang nanay sa kusina.	Mom is cooking in the kitchen.

2. SA marks direction. Prepositional phrases in English indicating some direction towards or away from a place, a person, or some other noun are also generally expressed asSA-phrases in Tagalog. Below are some examples:

Pumunta sila sa Zamboanga noong     bakasyon.	They went to Zamboanga last vacation.
Umalis siya sa klase nang maaga.	He left (from) the class early.
Ibinigay niya ang bulaklak sa nanay.	He gave the flowers to mother.
Kinuha niya ang libro sa akin.	He got the book from me.

3. SA marks the beneficiary of an action. It is equivalent to the English for-phrase in the context of doing something for someone/something. Look at the following sentence for example:
I baked a cake for Bill.
In this sentence, I let you know that I baked a cake, and I baked it for Bill. Bill benefits from my action of making a cake, so we say that Bill is the beneficiary of the action. In English, the beneficiary of the action is marked by the word for. In Tagalog, whenever SA marks the beneficiary of an action it always follows the word PARA (from Spanish meaning for).  Below are some examples:

Gumawa siya ng eksamen para sa klase.	She made an exam for the class.
Naghanda kami ng sorpresa para sa     tatay.	We prepared a surprise for dad.
Bumili si Ana ng regalo para sa asawa     niya.	Ana bought a gift for her husband.
Nagdala si Butch ng laruan para sa bata.	Butch brought a toy for the kid.

4. SA marks a future time expressed as a specific day/date/season.  Below are some examples:

May trabaho ako sa Lunes.	I have work on Monday.
Uuwi si Ellen sa Cebu sa Pasko.	Ellen is going home to Cebu at     Christmas.
Magtatapos siya ng pag-aaral sa      summer.	She is graduating in the summer.
Kaarawan ni Jun sa Pebrero 16.	It is Jun's birthday on February 16.

B.  KAY and KINA
The markers KAY and KINA take the place of SA when the noun being marked is a name of a person (like Bob, Jane,  etc.).  It occurs in the same way that SI and SINA replace ANG, or NI and NINA replace NG when dealing with personal names. KAY marks the name of a person, and KINA marks the names of two or more persons.  These markers have some of the functions of SA.
Functions of the markers KAY and KINA
1. KAY and KINA mark location. Here are some examples:

Nandoon kay Rudy ang libro mo.	Your book is with Rudy.
Naroon kay Tina ang gamit mo.	Your stuff is with Tina.
May salu-salo kina Aida.	There's a get-together at Aida's.
Nakatira ako kina Tiya Selma.	I am staying at Aunt Selma's.

2. KAY and KINA mark direction. Any prepositional phrase  that indicates some kind of movement toward or away from someone is expressed using one of these markers. Here are some examples:

Dadalaw ako kay Lola Sela bukas.	I am going to visit Grandmother Sela     tomorrow.
Ibinigay ni Ana ang susi kay Sally.	Ana gave the key to Sally.
Umalis siya kina Mrs. Santos.	He left (from) Mrs. Santos' place.
Itinago ni Luz ang libro (mula) kina     Pedro at Juan.	Luz hid the the book from Pedro and Juan.

3. KAY and KINA mark the beneficiary of an action. Just like SA, KAY/KINA-phrases are almost equal to English for-phrases expressing the idea of an action done for someone. The marker is always preceded by the word PARA (from Spanish meaning for).  Below are some examples:

Gumawa ako ng cake para kay Kit.	I baked a cake for Kit.
Binili ko ang bulaklak para kay Ida.	I bought the flowers for Ida.
Nagluto ako ng adobo para kina Rita     at Carlo.	I cooked adobo for Rita and Carlo.
Itinago ko ang mga sulat para kina    Susan.	I kept the letters for Susan and company.

4. KAY and KINA mark the possessor when it comes before the noun possessed. Structurally, the possessor-phrase is used as a modifier of the noun possessed. Thus,  the linker NA(i.e., -ng or na) is required between the two nouns. This function is limited to spoken discourse in its use. Here are some examples:

kay Mariang kapatid	Maria's brother
kay Bob na kotse	Bob's car
kina Litang hardin	Lita's family's garden
kina Mr. Ramos na bahay	Mr. Ramos' family's house

Putting the pieces together
Now that we have talked about the different types of markers, let's take a close look at how they work.
red=focused word (ang)   blue=relational word (ng)   green=location word (sa)

Dinala	ng doktor	ang elepante	sa ospital.
Carried (verb)	the doctor	the elephant	to the hospital.

The sentence above is saying that the doctor carried the elephant to the hospital. The word elepante is the focus of the sentence. Elepante is the most prominent part of the sentence. Because of the affix in the verb (don't worry, we will explain this later), we know that the focused word (elephant) is the one being carried. The marker sa let's us know that the elephant was carried to the hospital. Doktor is the relational word. Because of the context, the marker ng indicates that the doctor is the doer of the action (the doctor is the one carrying).
If we switch markers:

Dinala	ang doktor	ng elepante	sa ospital.
Carried (verb)	the doctor	the elephant	to the hospital.

This sentence is now saying that the elephant carried the doctor to the hospital. Doktor is now the focus and is being carried to the hospital and the elepante is now the relational word and is doing the carrying.
And now for one more switch:

Dinala	ng ospital	ang doktor	sa elepante
Carried	the hospital	the doctor	to the elephant

Here, the hospital carryed the doctor to the elephant. In order to fully understand how all this works, we need to understand more about verbs first. However, at this point you can see the way that a marker assigns a word its role in the sentence. If you change the marker, you change the whole meaning of the sentence! Cool huh?