Aquarius is socially awkward, but doesn't try to suppress his awkwardness. He's a gentle soul and isn't known for being very loud. Aquarius has a stammer, so pauses in his speech are recommended for his lines, just the right amount that feels natural. He only stammers when he's nervous or feeling self conscious though, but that's him for this whole comic so go ham and try things. lol
For Aquarius, I generally like to highlight that he's not human and comes from another world, so accents are welcomed with his role.