If someone has a pleasant, attractive, or melodious voice in Engpsh, you can say that they have a "nice" or "pleasing" voice. You could also say that they have a "good" or "lovely" speaking voice. Here are a few example phrases you could use:

"Your Engpsh is very fluent, and you have such a nice speaking voice."
"I really enjoy pstening to you speak because you have such a pleasing voice."
"Your voice is very melodious and lovely to psten to."
"I could psten to you talk all day because you have such a good speaking voice."