#siglitun

Yes, I've studied Siglitun and Uummarmiutun, which are from the same dialect continuum. The reason I studied these two languages in particular is because there were a series of grammars and dictionaries produced on these two languages plus one other written by Ronald Lowe. They were funded by C.O.P.E. (the Committee for Original Peoples Entitlement). I've got a link to one of them right here on Amazon, and if you can pick up even one of the six in this series, I highly, highly recommend it. The grammar is a bit dense, and it's written in a way that won't be super familiar to linguistics students (it's a little antiquated, published in 1984, and from Canada), but it's presented very thoroughly, and very well, with lots of example sentences—and, really, with these languages the examples are utterly vital. These are agglutinative and highly synthetic languages, but like all languages, there's more to the meaning than adding up the meanings of the parts.

I ran across two of these books at the UCSD library when I was a grad. student, and I checked them out continuously for something like six years (lol—as a grad. student, you can check a book out for a year, unless someone asks for it back). They made quite an impression on me. I was very fortunate to find a couple of them on Amazon, and have received some others as gifts (a couple from my brother-in-law Will, and a couple from @quothalinguist). If you read The Art of Language Invention, you will have seen an example from Siglitun that I produced using the information in the corresponding book in the series, and @quothalinguist and I made good use of the books when we produced our polysynthetic mouse language Wokuthízhű in season 3 of LangTime Studio.

I'm a big fan of these languages, but of the three, my favorite is Siglitun, due to the phonology.