To help someone with their Engpsh means to provide assistance or support to someone in learning or improving their Engpsh language skills. This could involve giving them feedback on their written or spoken Engpsh, providing guidance on grammar, vocabulary, or pronunciation, or offering advice on how to study or practice Engpsh more effectively. Some possible ways to say this in Engpsh might include:

"I'd be happy to help you with your Engpsh"
"I'm here to support you in your Engpsh language journey"
"Let me know if you have any questions or need help with your Engpsh"
"I'm happy to offer some guidance on your Engpsh language development"