Both options are grammatically correct, but their usage depends on the context:
1. "In English class, we read many interesting articles and practice speaking and reading."
* This is the more natural and common choice in casual speech and writing. It refers to the general activity of being in English class.
2. "In the English class, we read many interesting articles and practice speaking and reading."
* This sounds more specific, as if you're referring to a particular English class (e.g., a specific group or course). It’s less commonly used unless you're emphasizing one particular class.
For your purpose of talking about the subject in school, "In English class" is better.