Here are a few websites that you can use to work on Language Arts.
SplashLearn
ABCYA
ABCMouse
Newsela
PBS Kids
Starfall
Audible
IXL
Fuel the Brain
Adapted Mind
Adventure Academy
Free Kid Books
Raz Kids
Yapa Kids
Brain POP
Brain Pop Jr
Storyplace
Kids Read 2 Kids
Learning Works
Good Reads
Scholastic
Spelling City
Words Myth
Britannica Kids
Kids Discovery
Vocabulary A-Z
Loony Learn
Library for Kids
Word Wall
ESL Games