Resolved questions
when will they understand me. ?

shen2me（什么）=what
will=jiang4lai2（将来）
they=ta1men（他们 她们 它们）
understand=li2jie3（理解）=ming2bai（明白）=dong3le懂了
什么时候他们将会理解我？
shenme shihou tamen jianghui lijie wo？

I don't think it's a good way to learn chinese.
cas, we haven't the same logic of speaking.
so, the best way is
you know " 他们什么时候能理解我？" = "when the hell can they understand me?!"
it's enough, it's ok. you've got the model sentence.
so,她什么时候能理解我？= when can/will she understand me?
我什么时候能理解你？= when shall/can I understand you?
我什么时候能吃饭？ = when shall/can I have the dinner?
I'm sure you've know what I meant.

when=shen2 me shi2 hou4 什么时候
will=hui4 会
they=ta1 men 他们
understand=ming2bai2 明白
me=wo3 我
So when will they understand me ?
=他们什么时候会理解我？
ta1 men shen2 me shi2 hou4 hui4 li2 jie3 wo3?