Is it really necessary to start the sentence with the word both? It seems to me that simply saying: "Dima and Vera are their kids" is sufficient in this situation.
It is not necessary.
I couldn't hear the х sound
Strictly speaking, you have got the [ɣ] sound here because «х» happens to be followed by «д» immediately. Fortunately, this speech synth does pronounce this correctly (there are other tricky combinations, though).
"Both" is more acceptable here than in the previous answer but it implies that there might be some doubt about their parentage.
Dima and Vera are their children is correct in English. "both" is redundant and would be used only for emphasis
I was not able to hear well enoughto distinguish их, i heard another и, and thought it was just a strange fragment.
In normal speech Х is voiced in this environment, a bit similar to the consonant in "uh-huh". Depending on which languages you speak, that sound before a D may sound odd.
why is it used И this way here?
To express both ... and ..., use и ... , и .... :
However, in English "both -and" and "neither -nor" only can connect two things. In Russian you can extend this list by adding more elements with И (or НИ).
и вера и дима их дети I think It is right and should be accepted no dropdown for my sentence is right, because of that I could not report it. Where is the — at the keyboard?
Even if i say Dima properly they say it is wrong
How are we supposed to know when to put a - in the sentence?
It marks you wrong if you don't do it but the speach synths almost never pronounce a pause