Another syndicated article, datelined St. Petersburg, 18 May 1905, was picked up by two newspapers in the Newspapers Extra corpus:
WILL HE MAKE GOOD.
It is up to the Czar to Keep His Promise.
...All St. Petersburg and Russia in general are waiting today to see if the czar will make good his promise of last March to form a new branch of the government to serve as a connecting link between the emperor and the people. The new branch will be called the "Zemsky Soviet" and today has been set as the date of the proclamation putting it into effect.
These were followed by more widespread appearances in May and late October, 1905, in short syndicated articles documenting the creation of the Zemsky Soviet. One of the May articles, in the New-York Tribune, seemed to have been editorially altered to use the 'Sovyet' variation of 'Soviet'.
Of the October articles, another syndicated (AP) article appearing in the 26 Oct 1905 Leader-Telegram, Eau Claire, Wisconsin and other newspapers, describes 'soviet' as the "old name":
....
It is understood an edict formally establishing a ministerial cabinet which will bear the old name of "soviet," or council, will be published....
Substantially the same article appeared on 26 Oct 1905 in The Billings Gazette; that article had been locally edited to delete "old" before "name".
At about the same time (Sep-Nov 1905), articles in the popular press of both the UK and the US made mention of the Soviet Siezd (Council of Associations of Naptha Producers; Siezd is also spelled Sieza in these reports).
The tendency of these (and, presumably, other) mentions of 'Soviet' in the popular press was to firmly entrench the term as the English for a "Slavic council or governing body". At the same time, the occasional use of the orthographic form 'Sovyet' suggests the word was at least perceived by English speakers as having been adopted from Russian or another Slavic language.