Conversational essentials

Someone: biri

Biri (someone) points at an unnamed person. It behaves like a noun and pairs naturally with var.

There is someone in the house.
Evde biri var.
Someone is coming.
Biri geliyor.

Only: sadece

Sadece (only, just) goes right before the thing it limits.

I only want water.
Sadece su istiyorum.
There is only a cat in the house.
Evde sadece bir kedi var.

Supposing with sanmak

Sanmak (to suppose, to assume) makes a weaker claim than düşünmek (to think): you sanmak something you are not sure of. In the present it conjugates with -ıyor, just like the verbs you know.

What do you suppose?
Sen ne sanıyorsun?

Like This, Like That: böyle and öyle

This close pair describes manner, and the difference is distance — the same near/far logic as bu and o:

WordMeaningPoints to
böylelike thissomething here, something I am showing
öylelike thatsomething there, or what was just said

Öyle bir şey literally means "such a thing":

There is no such thing.
Öyle bir şey yok.
I want a house like this.
Böyle bir ev istiyorum.
Don't do it like this.
Böyle yapma.

Always: hep

Hep (always, all the time) sits before the verb or the predicate.

He is always at home.
O hep evde.
The man is always drinking tea.
Adam hep çay içiyor.