I am used to typing on a Ukrainian keyboard: I have never lost my ability to type on a French keyboard.

Learning to type in russian using 10fastfingers to improve speed, its quite good. occasionally I will go for the odd english letter "a" I've noticed. But overall getting faster I think.

В этом форуме следует писать только по-русски!

Answering my own post here. I've learned the keyboard using https://www.keybr.com. I can confirm that it doesn't interfere with normal typing. I don't need any stickers anymore and can use any keyboard as long as the layout is installed on the operating system. I'm still on my way to becoming faster (snail pace atm). I would recommend. Its a valuable investiment.

I switch between english and russian keyboards often. To help you in the beginning you may want to apply russian keyboard stickers. As you get more proficient, you will be less reliant on the stickers.

It only "messes" with your English typing if you stop using your English layout. I use 4 layouts daily for French and English, Japanese, and Russian and only struggle when I've mixed up which one I'm using and have to reset my muscle memory in my head. At worst it took maybe ten minutes to do the switch and I was fine again. As an illustrator of that, I typed this in my two Latin layouts with only a minor drop in speed right after I switched and I picked up again within 30 seconds. It's not anything to worry about, I would say.

And as for the Russian layout I use, it's «Русская (международная) раскладка клавиатуры» since it gives access to guillemets and some other necessary symbols unfortunately absent from the standard Russian keyboard. It's not phonetic as I believe it's best to learn the standard if you ever have to type on a Russian keyboard that isn't your own.

I use both keyboard layouts every day. I do not use any stickers on the keys during many years because I had to have business trips in Europe. I wanted to be free on any computer with any keyboard. Sometimes I make mistakes while typing.

Этот текст я пишу на той же стандартной немецкой клавиатуре без русских букв.

I've only done it a little. I have a copy of the old, old, old 1950s linguaphone course but the pdf is scanned not text so I can't copy and paste.

I tried to type the lessons out using the on-screen keyboard.

It's doable but painful one letter at a time. I've done maybe 10 hours total. I have started to learn where the keys are but even now I still have to scan to see where the different letters are.

I don't think it really does affect english though to be honest simply because it's too different.

I've gotten fairly used to the Russian layout on my phone, but that's not the same as touch-typing which I do effortlessly on a real keyboard in English and, as @ftornay suggests, with a phonetic Russian keyboard. There are a few variations of those. The YAWERTY (or YAWERTY2?) keyboard that I use has Russian "В" mapped to "W", which does make some sort of sense, though you'd be justified in thinking that "V" might have been a better choice. I've seen the location of ё and Ё vary a bit between various implementations, along with ъ and Ъ. Nevertheless, it took little time to get used the implementation that I use, and I can type as fast in Russian as I can in English, even when there is not a phonetic relationship between the English key and the Cyrillic character it maps to.

I use a _phonetic_ keyboard layout and it works like a charm, I can touch type both in latin alphabet and Cyrillic with no problem whatsoever and it took me very little time to get used to it. And it won't mess up your English typing skills.

Here you have an explanation of what phonetic layouts are and kinds there are:

http://winrus.com/kbd_e.htm

The part about how to install them is very outdated. What system are you on?

In some modern OS you can just look for "phonetic Russian" in the list of keyboard layouts. I downloaded a layout file for ubuntu and added some more keys. If you're interested, let me know and I'll give you a link to it.

It's not necessary to use a russian keyboard to type russian. You can use what is labeled a russian "phonetic/mnemotecnic" keyboard, which is basically: each cyrillic letter is typed with the closest sound of the latin alphabet

It;s easy. Just get some russian keyboard stickers. Apply them to your keyboard (I like the transparent ones). Then set your keyboard to toggle between english and russian. In windows it is in settings under time and language. Select Russian and you will be able to switch languages with a single click. I now no longer need the keyboard stickers and they have mostly worn off. I also learned to handwrite in Cyrillic.

My English typing doesn't interfere with the russian one at all, it feels as the two independent sets of muscle memory. I can't speak for how it goes with 3rd language though, hope some time.