What it says. Language spoken by majority of people living in Hokkaido or Kurils or Sakhalin or Russian maritime province is English, Spanish or Scottish by 1850.
An English speaking Hokkaido is more than achievable though. There was an incident in which the British tried to attack Dutch ships in Nagasaki in 1808. Perhaps if the Saga clan were better prepared than it could lead the Japanese sinking HMS Phaeton perhaps. That would mean war or the British wanting some revenge at least so they would do what the Americans did later on and perhaps as part of the treaty the British get Hokkaido and decide to use it as a Settler colony to keep a grip on the island and to help use it as a base in case anything happens against Russia.