Every language can describe any color, in some way, but the categories of colors sometimes differs.
Many languages, across many different language families, including the one English belongs to (Indo-European), considered orange to be a shade of red or yellow. Orange as a distinct color came later.
Japanese originally considered green and blue to be shades of the same color. Japanese later got a word for green, and the the green/blue word now means blue, most of the time. But a few things Westerners consider green, like traffic lights, use the Japanese word for blue.
I am sure the Death Bunny was right. Some shades of blue most languages have, like English, are different enough to be considered different colors.
Just like us now considering orange to be a distinct color, but some languages consider it a form of yellow red.
It is never the case that a language would not be able to describe the color of the sky or the sea, or recognize that they are not exactly the same color. It's just a matter of which words and how many words are needed to indicate the difference, when they care about it. Normally, English speakers don't care if it's a dark or light blue, for example, but some languages do.