Last night I passed an elderly American Indian woman wearing a sweater from some sort of camp or event by this name.
How the heck do you wrap your tongue around that? I know Native American languages tend to have some interesting lexicography, but i’ve never even seen a colon as an accent mark before.
The Skway First Nation, officially Shxwhá:y Village.
According to this site, it’s pronounced “Sh-why”.
I am not a speaker of this language but I think the colon lengthens the preceding sound. Just like how it works in IPA. They are members of the the Sto:lo people, and that page gives pronunciation. The speak Halkomelem, but I don’t see anything about the colon there, but the rest of it can be deciphered.
That’d be the Skway First Nation.
The language is apparently Halkomelem and the colon lengthens the vowel. That might not help a lot though!
BTW, is it just me that sees Google Autocomplete switch to Hebrew when typing “shx”? 
Looks like Halkomelem to me, a Salish language spoken around Vancouver. For the writing system you can thank my former professor, Brent Galloway, who developed it in the 1970s. The colon signifies a long vowel; this was probably fashioned after the ː symbol in the international phonetic alphabet.
Prof. Galloway’s classes in theoretical linguistics always made liberal use of Halkomelem examples. For the exercises I can remember having to annotate pages upon pages of Halkomelem sentences despite not speaking a word of it…
Answers like these are why I love the SDMB. And all within 15 minutes of the OP.
The x in American Indian languages stands for the sound of /x/, which is the ch in Bach or chutzpah or the kh in Khrushchev. Unvoiced velar fricative. The colon being the sign for a long vowel is correct.
The pronunciation would be approximately sh-kh-WHY. I think they left out the /x/ sound as a simplification for English speakers who aren’t familiar with that sound. Kind of like people named Nguyen saying you can just pronounce it “win,” even though that leaves out half of the phonemes.