Can someone tell me, are these sounds reliable?
It's often very hard for me to tell what the voice is saying, and sometimes I can't see the relation between the audio and the written form. Ребенок in this sentence sounds like "digörk" or "digörök" to me, no matter how many times I listen to it. In another sentence it sounded like "eridörk".
I've understood that in some words the letter o may sound more "closed", depending on the other letters in that word. That could explain why the o sounds a bit like ö. But what explains the rest of these changes in the audio? Are my ears just that bad?
Duo's sound is wrong. As is Google Translate (which might be where Duo got its audio clip from).
http://www.lingvo-online.ru/ gives a standard rendition of ребёнок with the Russian p rendered as something close to English R. It is easy to hear the Russian p sound which it should be in this word.
You are correct that some vowels can sound more open or closed depending on the circumstances or speaker but the P in ребёнок should be easily distinguished for what it is.
If you are using windows just do a search.
First search for the appropriate procedure to install the option to toggle/click to a keyboard mapping for Cyrillic. Don't try to use some sort of cheat method to arrive at a Russian letter system. Just install the Microsoft apps which are free and simple to download. Some of the necessary steps are already on your computer.
Then search for a free typing in Russian course. If you can touch type it will take only a half hour a day for a couple of weeks to be able to comfortably type with Cyrillic.
And yes, you are correct. Being able to use the alphabet as Russians do will make it easier to pronounce the words as Russians do. A lot easier actually.
@GiulianaOr12 - In most printed Russian sources (blogs, news articles, technical documents, etc.) you won't see ё, just е, so you do have to learn when it's a ё and not a e (there are some good general rules that are a little more advanced). In this case, there is only one word - ребёнок - but because they are less prone to writing the ё you will more frequently see it spelled ребенок. Just remember that second e is a ё. Long story short, they are pronounced the same (re-BYO-nuhk).