Matai

I think it's just another word from a native language from Sabah.
It sounds like "Mati- from Malay.

Meaning: Die.

"Matai"

(In Malay)
A: Matailah kita.

(In English)(For the sake of translation):
A: We're dead.
(Or "We're done for")

Sial

Commonly used as a curse-word.
It's a word from SEA (South-East Asia).
Somehow, it could mean "bad luck" or something along the lines of "hardship".

But commonly used like when you say "Shit!".
(But it doesn't mean "Poo")

It may also be used to address someone rudely.
(Which you could translate to "Shithead")

Other variants of this are:

-"Sialan" (Another way to say "Sial")
-"Be(r)sialan" (Meaning: Being a shit or shithead)

To exclaim or simply curse, you say: Sial!

To address someone rudely, you say: Hey, Sial.

Budukang

Another variant of the curse-word "budu".
Occasionally used to make the word (budu) sound funnier.

Budukang tul dia ni.

Bah

A very Sabahan word.
It is similar to "Ok".

It's so common in Sabah.
And it works just like the word "Ok".

Sometimes, people use "Ok" and "Bah" together.
Which just makes your "Confirmation" sound more emphasised.

A: Kau pigi sana kadai nanti.
B: Bah.

(Using Bah and Ok together)

A: Kau tulung sia bikin ni nanti, buli?
B: Bah, ok.
(or)
B: Ok, bah.

Translations

A: (You) Go to the shop later.
B: Bah.

(Using Bah and Ok together)
A: Can you help me fix this later?
B: Bah, ok.
(or)
B: Ok, bah.

Sika

It is a "word" or just an exclamation that Sabahans commonly use to say "Shoo!".
Specifically to a dog.

That's all there is.

Oh, and another variant:
-Sika po!

A: Sika! Anjing, budu.

(With the variant)(Basically the same thing)
A: Sika po! Anjing, budu.

Palis-palis

It's a..... "Charm Word"?
Is that what you call it?

Well, it's just a phrase you could occasionally hear Sabahans say when they fear that something might happen.
Usually a bad thing.

It's like a phrase to repel a jinx.

At the same time, people might "knock" on something while they say this.

And there's another variant:
-Palis-palis, jauh-jauh

"Jauh" meant "far".
Since it's pluralised, then it means either "far away" or "go away".

And idk what "palis-palis" means.

(In Malay)
A: Sia dingar-dingar ada urang pigi mencuri di kawasan kampung ni.
B: Uish, nah. Harap-harap dia kana tangkap pulis -lah tu.
B: Janganlah lagi dia pigi mencurilah.
A: Odoi, palis-palislah. Jangan begitu.

(Translation)
A: I've heard that someone's been stealing in our neighbourhood.
B: Whoa, hope they get caught by the police soon.
B: Hope they just stop stealing though.
A: Yeah, hope they don't go stealing anymore.

pikir

It's just another way to say "fikir" in Sabah.

(In Malay)
A: Kau pikir kau buli?

(Translation)
A: You think you can?