Native Americans are granted more leeway and eventually get their own states or local governments early in US or Canadian history. Many more native languages are recorded in time and survive with greater numbers of speakers.
Some missionairies, Catholic or Protestant, start recording native languages more thoroughly everywhere they go. The result is better surviving documentation of particularly small or more marginal languages. Maybe there's some influential Catholic movement or some ATL Protestant sect that deems it worthwhile to record the languages and culture of the natives and preserve them from destruction, even if they're intent on converting them.
An effort similar to the Welsh language revival is started sooner in Cornwall and Man, preserving enough native speakers for the languages to survive intact long enough for a more fluid revival. Like in Wales, the languages don't temporarily die out, just enter a moribund phase for a while, before the number of native speakers starts growing again. Cornwall probably needs some cultural autonomy recognition sooner, as it would not be granted its own government, like Wales. Man has the government, but you'd need different types of incentives to avoid Manx teetering on the edge of extinction.
Ireland also abandons the purely Gealtacht-focused, "open-air museum" approach to preserving Irish. Its government and institutions try to come up with ways on how to get more people in the big cities and the more anglophone part of the country to speak Irish on a casual basis. Irish undergoes some grammar and pronunciation modernisation to make it slightly more easy to learn.
Modern Poland dodges communist takeover and in the post-war democratic period, takes a somewhat more post-1970s Spanish approach to its native languages, with Mazovian being revived or strengthened, besides support for Silesian, Kashubian and Goral like in OTL.
The Baltics are the real tough cookie when it comes to Europe. Plenty of interesting languages to save there, but I'm not quite sure how deep and vast the POD should be.
Something happens in the late Middle Ages that anchors and supports the Czech Jewish community more thoroughly, leading to them having something of a protected status in the monarchy, and this leads to more pockets of
Knaanic surviving. It goes extinct by the 19th or early 20th century, and if the persecution of Jews in WWII is avoided or smaller than in OTL, some Czech Jewish enthusiasts might attempt to revive Knaanic later in the 20th century. Fast-forward to some living history festival in the 21st century and some Czech Jewish reenactors are heard speaking Knaanic at a reenactment event.