With great difficulty.

Close relatives, British, white, honest – Mum, Dad, girls 4 & 12 - moved to Costa Del Sol, Spain. Before going, Dad learnt Spanish. Determined to integrate. Historically, some British tourists cause trouble, so local Spaniards wary.

Girls went to Spanish state school. Different – blonde and redhead. Spurned. Teachers unsupportive, but girls managed to learn Spanish. Spanish classmates invited for birthday parties – never invited back. Mum & Dad waited outside school for the girls, chatted with Spanish parents. No friendships ever made. After 5 years Dad gave up integration.

Young-retired friend, British. Often to Germany for dances. Made good friends. Enough German to get by. Decided to move to Germany. After a few weeks - returned to England. Outside dancing his friends had other social lives; his German not good enough; apart from dancing the topics discussed were local & outside his knowledge.

If these migrants had been RAISED in their target country there'd have been no question of assimilation. So, difficulty in assimilation is not DNA, it’s cultural.

British friend lived in London. Area changed character as Indian people moved in. Not too bothered – new people quite private. One day he saw an Indian man defecate in the street. Not unheard of in India. If the man had just arrived, how would he know that public defecating is taboo?

Equally - British abroad are sometimes unaware / dismissive of local customs – e.g. going topless is most offensive to some.

So cultures clash. So people stick with their own. So children, who may attend indigenous schools, spend more time within their parents’ culture than with the host culture – the problem continues.

The American musical “South Pacific” is set in WW2 on a Pacific island. American servicemen await orders. One falls for a local girl. It’s clear they will marry. But when it comes for him to take his girl to USA he cannot. He sings a short, brutal song, “You’ve got to be carefully taught.” Lyrics here: https://genius.com/Richard-rodgers-youve-got-to-be-carefully-taught-lyrics.

The most telling lines are, “Before you are six or seven or eight / To hate all the people your relatives hate”.

This works both ways – for the indigenous population AND the immigrant.

For me the answer is education. Every society should teach openness. But, for the time being, attitudes are too entrenched, and how to break out from physical and cultural enclaves seems impossible.

In assimilating, I think it's important to remember that the immigrant is adding to his or her societal and cultural understanding, not replacing it. Learning cultural and societal cues and norms are important in assimilating. It may help to befriend and observe a citizen who was born within the country. Picking up a sport or activity, joining a club with other assimilating immigrants, enrolling in local classes, attending churches, eating out at local restaraunts, and just in general observing the societal norms of citizens are all ways to begin assimilation. Citizens of the new society can also benefit from being exposed to the cultures of new immigrants, making sharing just as important as assimilating.