How long does it take an adult with poor English foundation to go to America to win English?

English is still a headache for adults.

Your English foundation is poor, depending on the degree.

There should be English classes to help immigrants in the United States, but they are not very helpful.

The key depends on your circle.

If English is widely used in your work environment, it will be faster.

It also matters whether your personality is cheerful or introverted. Will you come into contact with English if you have the chance?

If you really work hard, there should be no major problems in listening in 1-2 years, and you can basically communicate in spoken English. Given your work, writing may be different.