Greetings
السلام عليكم
as-salaamu alaykum
Peace be upon you — the standard greeting; reply 'wa alaykum as-salaam'.
كيف حالك؟
kayf haalak (to a man) / haalik (to a woman)
How are you?
الله يعطيك العافية
allah yaʿteek al-ʿaafiya
'May God give you wellness' — a very common Saudi way to say thanks / well done.
من فضلك / لو سمحت
min fadlak / law samaht
Please / if you please.
Social
تكفى
tikfa
A heartfelt Saudi 'please' / 'I'd really appreciate it' when asking a favour.
خلاص
khalaas
Done / enough / okay — an all-purpose Saudi filler word.
Daily life
وش هذا؟
wesh haatha
What's this? — 'wesh' is the Najdi word for 'what'.
بكم؟ / كم السعر؟
bikam / kam as-siʿr
How much is it?
Food
الحساب لو سمحت
al-hisaab law samaht
The bill, please.
موية
mooya
Water (colloquial; 'maa'' in formal Arabic).
Work
إن شاء الله
in-shaa-allah
God willing — used constantly about anything in the future.
Emergency
النجدة / مساعدة
an-najda / musaaʿada
Help! — for emergencies.