Some x (a) little: Qual utilizar

Neste caso, ambos podem ser utilizados. Eu mesma, sempre vejo americanos utilizando as duas formas.
Mas o "little", quase sempre soa como "pouquinho".

Quando está falando de quantidade:

Some water = a little of water = um pouco de água

To me "I wanna drink some water." is more natural.
With a "little" it sounds to me that there´s some kind of limiting situation (aka "limiting or negative meaning" topic on the subject).
And as pointed out by Andrezza, some would mean generally speaking "a little of water".

Explaining further: If I said "I wanna drink a little water", to me it suggests that I a so critical state that a little water would do. Perhaps I am on IV feedings and "a little" would mean wonders for me!

To, others drinks, liquor/whiskey for example I have seen examples with "little" on the web.
Even so, there aren´t many of those, compared with "some".

Granted, you could use both ways. I have seen from reading the case of "a little money" meaning "some money".
So, that´s okay, less used with "water" but okay.

https://www.ego4u.com/en/cram-up/vocabulary/little-few