1881-1882: CW & Métis French on the upper Columbia in Washington
Both of the Pacific NW Métis languages show up in a couple of later frontier narratives of north-central Washington…

“A glimpse of the Grand Coulé[e]” by Alfred Downing (image credit: Skagit River Journal)
Symons, Thomas William. 1967 [1882].
“The Symons report on the upper Columbia River & the great plain of the Columbia.”
Fairfield, WA: Ye Galleon.
Local language-wise, Symons seems to have registered only the fur-trade era French of “Old Pierre”, the 70-year old Iroquois former voyageur who was guiding the expedition.
Downing, Alfred. 1980 [1881].
“The region of the upper Columbia River and how I saw it.”
Fairfield, WA: Ye Galleon.
Downing’s nonstandard spellings of CJ, and the fact that he seems to have noticed Jargon being spoken (Old Pierre “could talk Chinook like an Indian”) while Symons didn’t, suggest he’s relaying actually observed usage.
I love when that happens.
Downing (p. 33) quotes the fascinating phrase “skoo-kum hyas kloshe tsum” (a ‘strong excellent writing’) for a letter of recommendation written by a non-Indigenous person in a position of authority to vouch for the character of an Indigenous person.
This is what was called a “skookum paper” in Alaska in the same period.
The overall picture we get is that Jargon was current on the upper Columbia & tributaries in the early 1880s.
Local Indigenous people (mostly Salish up there) seem to have used it with non-local ones like Old Pierre, and with non-Indigenous people.