By the way about language stuff. Vulcans greeted humans in English. Sooo, by the time of the first contact, Solkar could say at least one sentence in legible English?
The question is why, if they didn’t originally plan to visit Earth. According to “Federation: The First 150 Years” (which is not, like, 1000% canon, but i still like it and use it as base in many cases), the goal of “T’Plan-Hat” and her crew was our Sun, its activity and potential wormholes in the area.
For a couple of hundred years, the Vulcans have been watching the Earth out of the corner of their eye even before the time of Carbon Creek, but they are unlikely to have gone much deeper: given that during this time humanity has spit out half of the planet and population with nuclear stuff, it def didn’t not look like it was close to overcoming the speed of light. But they had some idea of earthly languages. About English - definitely yes, esp about American English - again, Carbon Creek.
This means that they have some kind of dictionary, albeit raw, at that time. And some corpus of texts. (well, they had to google "Live long and prosper" somewhere for that couple of hours of flight and landing. With transcription or audio recording of pronunciation. Bc the languages of pre-warp civilizations are obviously not taught at the Academy by default, are they? And Solkar is not a linguist by profession - he is an astrophysicist and a xenobiologist, only later a diplomat. So, among them were some wild xenoanthropologists who were fascinated by T’Mir and Stron's reports on the Earth and who had a burning desire to learn English and collect a database?
(Hc that Solkar learned English more thoroughly later, and he worked on his pronunciation with the help of old news programs and documentaries. Therefore, at first, taking into account the specific vocabulary (a bunch of professional terms, the absence of vernacular, dialectisms, idioms, and even more obscene vocabulary), he sounded like a pre-war earthly radio announcer)
