Don’t write Bisi, write B.C.
One of Father Le Jeune’s tidy little charts that can be so fun:
“ABBREVIATIONS”
Pus msaika tiki mamuk
If you folks want totanas iht iht nim, tlus msaika tlus nanich ukuk:
shorten this or that name [in Chinook shorthand], you should pay attention to this:
<1o> mun klaska nim:
1. names of months:<1o> Shanwari = Sha. <7o> Shulai = Shi.*
1. January = Sha. 7. July = Shi(?)<2o> Fibrwari = Fi. <8o> Ogyust = Og.
2. February = Fi. 8. August = Og.< 3o> Marsh = Ma. <9o> Siptimbir = Sip.
3. March = Ma. 9. September = Sip.<4o> Ipril = Ip. <10o> Oktobir = Okt.
4. April = Ip. 10. October = Okt.<5o> Mi = Mi <11o> Novimbir = No.
5. May = Mi 11. November = No.<6o> Shun = Shun <12o> Disimbir = Di.
6. June = Shun 12. December = Di.
Ilihi nim:
Village names:Kamlups = Mk. Shugir Kin = Sh.K.
Kamloops = Mk. Sugarcane = Sh.K.Chokchokwah* = SShB Alkalai Lik = Alk.*
Chu Chua = SShB Alkali Lake = Alk.(?)Skishistin = Sk. Knim Lik = Kl.
Skeetchestn = Sk. Canim Lake = Kl.Shhkaltkmah = Shkh. Kanu Krik = KK*
Sahhaltkum = Shkh. Canoe Creek = KK(?)Duglas Lik = Dl. Soda Krik = Sok.*
Douglas Lake = Dl. Soda Creek = Sok.(?)Kwilshana = <Q> Hai Bar = Hb.
Quilchena = Q High Bar = Hb.Kol Watir = Klwa. Bonapart = Tl.
Coldwater = Klwa. Bonaparte = Tl.Nort Bind = NB
North Bend = NBSpisom = Sp.
Spuzzum = Sp.Ilo mamuk cim Bisi; mamuk cim <B.C.>
Don’t write “Bisi”; write B.C. [in English letters].
I won’t go into it now, but the above abbreviations are formed in two or three different ways. That’s why I represent them variously in transcription, with some all in capitals, some with initial capitalization and periods, etc.
And you’ll notice that some of the abbreviations actually stand for the (Chinuk Wawa) name of the village, but others diverge a lot. In the second case, what’s usually abbreviated is then the Indigenous name of the place, such as “Tlohtaws” for “Bonaparte”.
“Bisi” really was used. I have found it in the shorthand letters written by Indigenous people. Here, Le Jeune is advising his readers that shorthand “Bisi” won’t work when you address an envelope!

Bisi
The abbreviation for “shulai” is “shai”, as in “Jy.”, which is now rather old-fashioned in English.
Hi David, thank you very much for reading, commenting and making me take another look at this!
I actually think I misread at first — it’s almost certainly intended as “Shyu.”, the first syllable of “July”, using the same approach as with the other month abbreviations.
“Shai” seems improbable to me, as I doubt anyone pronounced the English “Jy.” that way, just as nobody pronounced “Jno.” any other way than “John”.
Best from
Dave Robertson
(It doesn’t help that the image is blurry just where the abbreviation for July appears!)
The image as it appears in this post is blurry, but at https://open.library.ubc.ca/viewer/kwawa/1.0347397#p8z0r0 it is much clearer, where it really looks like “shai”. “Shyu” wouldn’t make as much sense because the full word is “shulai”, not “shyulai”.
Fair point! And “Shyu” wouldn’t be much different from the full word “Shyun” (June)!