If their English is that bad and the studio isnt providing English tutoring (most of the studio's I know of and the few that I have worked in have provided this) the best thing they can do is move to a better studio IMO. It could also be that the studio does provide English tutoring but the models decide not to take them up on it because it would be unpaid, I have seen this a fair amount too.
As for helping them with marketing, a good place to start learning is the Crakrevanue blog
https://www.crakrevenue.com/blog/ and digital marketing forums.
Traffic generation is a huge job, people spend years and thousands of dollars learning how to do it correctly, it's not quite as simple as just dropping links somewhere and waiting for the clicks (much like everything there is no such thing as free traffic, if you dont pay for it in $ then you need to pay for it in content).
The marketing that you are able to do is also going to be limited by their contracts with the studio, it's likely that you wont be able to use the images, videos or liveshow content without the approval of the studio, so you would need the model to put you in touch with the studio owners to get approval on any content you wanted to use for marketing and how that content is going to be used.
The best way you can help is buy tipping in the room which will encourage others to join in to reach the goals.
I do web design and development, but like 99% of people that are able to do bio designs and code them, the time it takes to design and develop it would need to be paid and because the studio owns all the rights to the models image and likeness they would have to be looped in and approve the design and the use of the images., this is why studio models tend not to have custom bio's outside of some basic images unless the studio has a web dev on staff, or the model is earning a lot and the studio wants to keep her happy to prevent her from leaving.