Parents and teachers - focus and praise your children for what they can do.
Ask them what they CAN say in English.
DO NOT test them by asking random questions they may not know: "What is ~~ in English?" Unless you are sure they know, or you genuinely want to test them and put them under pressure, but if you do that too often you could demotivate them...
Most children only get the opportunity to use English once per week. Homework is there to give them an extra opportunity in the week to have exposure to English, not just to make them busy. It helps keep their English fresh and fast.
It is a good idea to do home work at least about half way between their lessons. Best would be to practice a little every day - as you would expect if they were learning a musical instrument...
It is better to do something and make mistakes than to do nothing for fear of making mistakes.
Mistakes can be corrected, learning takes place, and improvement is made.
If nothing is done, there is nothing to be improved upon.
If language is produced and mistakes are not made, then the studying moves on to the next level where mistakes will initially be made.
This is often why many students will say "it is difficult". Newer concepts are usually difficult until they are internalised and practiced enough times that they become automatic.
Look at what students could do 6 or 12 months earlier to see how they have progressed, not how "easy" or "difficult" they think it is.