Learn Turkish: Şu bir kedi.

In Turkish, for the present tense of 'to be' with 'he', 'she', 'it', or 'that' (the 3rd person singular), you often don't need to add any ending or word at all. The fact that it is a statement makes the 'is' understood. So, Şu bir kedi literally translates to 'That a cat', but it means 'That is a cat'.

I thought the word for 'that' was o. Why are we using şu here?

Both o and şu can translate to 'that', but they are used differently based on distance. O is used for things far away or out of sight. Şu is used for things that are a bit closer, or when you are physically pointing something out to someone for the first time (like saying 'Look at that!').

Do we always have to use bir (a/an) when identifying objects?

Not always, but it makes the meaning crystal clear. If you just said Şu kedi, it could mean 'That cat' (as the subject of a bigger sentence) or 'That is a cat' depending on the context. Adding bir acts as a bridge that makes it undeniably clear you are saying 'That is a cat'.

Since şu means 'that', is it always translated that way?

Not necessarily! It falls right in the middle of Turkish distance words. Turkish has three: bu (this, right here), şu (that, a bit further or pointing it out), and o (that, far away). Because English only has 'this' and 'that', translating şu into English can sometimes be 'this' and sometimes 'that', depending on what feels most natural in English.