In my opinion, the United States is one of the best places to live. That's why we've attracted many folks from other countries and we now have many in the work force who don't speak English. 40 years ago, it was rare to find anyone in construction who didn't speak at least passable English. That's changed.
When you are looking for employees, your advertising should include the caveat that speaking, reading and writing English as a job requirement. Your employees need to be able to communicate with clients on the job site, regardless of the work they do. Customer satisfaction is critical, and if clients can't communicate with the person working in their home or on their property, they might not be happy.
On the other hand, sometimes the best employee available doesn't speak English well. If you have employees who speak English as a second language (or not at all) and they are good employees (they know their jobs, show up on time, work hard and give you a days work for a days pay) maybe it would be worth your time to help pay for ESL (English as a second language) at a local school. I know several contractors who've done this and not only did they get better employees out of the deal, those employees appreciated the effort and were more loyal to the company that helped them. Their fellow employees were also able to communicate better with them, and it became a win-win for everyone.