Most of those countries have special Commonwealth migration arrangements with the U.K. anyway. They were able to have this when we were in the EU, too.
It has been our governments’ policy not to train our own medical graduate and employ them for decades and decades (across both left and right wing parties). Places on medicine courses are subject to quotas. We deliberately under-train our workers so that we can fill jobs from workers trained elsewhere. We also under-train our young people in general, loading them up with debt for tertiary education and training and instead importing workers from elsewhere to fill skills gaps.
If you want to change this: great! Just know that is not remotely what Reform want to do. That would require massive expansion, funding and renationalisation of higher and vocational education, and Reform voters, who uniformly parrot the “too many graduates / Tony Blair fifty percent” bollocks, very especially don’t want that.
In fact, you can’t say in one breath that you want to open up high skill jobs to China and the US; and then in the next claim we should be training our own kids instead. Those two things are not really compatible with each other (and Brexiteers/Reformers don’t really want to pay for educating anyone. They most particularly do not want to pay more tax so that we can expand universities and vocational training in order to educate British kids to a higher skill level).
And why do you think so few Britons speak another language? First, because it’s not valued in our society; but recently, more tellingly, because Michael Gove (a Brexiter) included in his reforms to the school curriculum measures explicitly to downgrade languages in state schools. As a result, hardly any schools teach languages now; and since 2010 the number of children studying two languages at school, something that was routine even in comprehensives when I was at school, is now a vanishingly tiny proportion of the cohort.