this (person/thing)

In the example above, the speaker uses "this" instead of "a". There's a small difference between the two. When you say "this ___" it sounds like you're talking about one specific thing. "A ___" is more general. 

You use "this ___" instead of "a" or "the" when you're introducing something specific that you're going to talk about. It's usually used at the beginning of a story or explanation. For example:

Amy and I were sitting there talking and this guy I know walked by.

I've had this song stuck in my head for two days!

Today I was talking with this girl at work who just got back from maternity leave.

In all of these examples, the speaker will continue by telling a story about that topic.

People only use "this ___" in this way in casual spoken English.

this weird (verb+ing) noise

You can use this phrase when you’re trying to describe an unusual sound you heard.

There was this weird thumping noise. I was really freaked out.

She makes this weird chattering noise when she sees a bird.

screeching

A "screech" is a high-pitched, unpleasant noise. Some things that "screech" include:

• An owl that is about to attack a mouse
• A car engine that's having some trouble

(something electronic) died

We say this when a device turns off, either because of a dead battery or an unknown problem.

I think her phone died; it’s going straight to voicemail now.

I got about ten years of use out of it before it died for good.