Learn Turkish: Bu bina bir ilkokul. - This building is a primary school.

In Turkish, the 'is' part of a sentence is often represented by a suffix (like -dir). However, for simple statements about what something is, this suffix is frequently left off. You just say 'This building a primary school,' and the 'is' is understood!

Since we are learning the locative case (-DA), why don't we say Bu binada here?

Bu binada means 'in this building.' If you wanted to say 'There is a primary school in this building,' you would use the locative case and say Bu binada bir ilkokul var. But here, the building itself is the school, so Bu bina is the subject and stays in its plain form.

Is ilkokul made up of two different words?

Yes! It is a compound word made of ilk (first) and okul (school). Turkish loves gluing words together to create new concepts!

Could I leave out bir and just say Bu bina ilkokul?

You could, but including bir (a/an) sounds much more natural when classifying what a single object is. It perfectly matches the English feel of 'is a primary school.'