‘Ali ali’ is not a measurement

It means “a little”. That is the dictionary answer and it is almost useless, because ali ali is not a quantity — it is a position.

• Asked how much chilli you want: ali ali means “some, but I am signalling that I do not want to be a problem”. You will receive a normal amount.
• Asked whether you speak Nepali: ali ali covers everything from four words to genuine fluency. The fluent are the most likely to say it.
• Asked whether you are unwell: ali ali means you are quite unwell and would prefer not to make an announcement about it.
• Asked whether the food is spicy: ali ali from the person who cooked it is not a measurement. It is a warning delivered as a courtesy.

The pattern underneath all four: ali ali is rarely about amount. It is about not taking up space with your answer. Which is why the honest translation is usually not “a little” but “let us not make this into a thing”.