excellent knowledge of English with some having even a slight English dialect from when they were in UK !
Mr Mac
Which can often be quite surprising. The Indian waiters at Faslane with broad Glaswegian. The German, with immaculate American English of another German woman with good English "she is very common, you can tell from her German" and a French exchange school girl , beautiful English but very coarse French.
Finally a French waiter in Biarritz, immaculate English that 'e 'ad learnt in 'alifax. 😀
PS, met a young man from Singapore, also immaculate and idiomatic English. Until two years previous he had had no English at all. It can be done.