The Ukrainian language, while similar in many respects to Russian, is like the differences between Lithuanian and Polish.
A Ukrainian may understand a Russian, but the dialect and many words differ. It is rather like an Austrian or a German Swiss speaking to a native German.
It is synthetic. More like ‘old’ pre-18th century Russian with little Polish influence. Russian and Ukrainian are mutually intelligible.
In 1989 maybe 15% of Ukrainians spoke it, mostly very old and rural people.
Today it is fashionable and maybe half try to speak it but they do it poorly. That they speak is known as ‘surjik’ - a weird mix typical to that people call Spanglish. A mix of semi-forgotten Russian and never properly learnt Ukrainian.
Put some stress on them and 90% switch to clean Russian.
Or like someone from Spain and Mexico.
But in any case. The gold dust twins from Ukraine work in the white house, work on the NSC. And they were hired by Fiona Hill, who was born and raised in the UK. Camel jockeys are a dime a dozen.
Foreigners are crawling all over the white house.