Sentence:  Old materials on O1, Dharuk, give 1du as "ŋala" or "ŋalu" and there is no explanation for the final vowel (note, though, that "ŋali" is found in the closely related language O2, <WSD>Darkinjung</WSD>). 
Meaning of the word marked with <WSD> tags:  The extinct language of the people of that region.