"Haaj" is a Dutch slang term for "Hey" or "Hiya" . It is used as a welcome term (See example)or to greet a friend informally . Dutch teenagers are the usual suspects to use the word and the word is also heard in parts of Belgium and Dutch-speaking areas in France .
Pronunciation : Similar as the English word "Hay" with a slight rounding of the mouth when pronouncing "Ha" .
"Haaj! How are you?" Informal greeting (Cannot be used as formal)