Answer just for some words in Russian:
There are some sites on the web that offers a keyboard in several languages.
Just type "Russian keyboard online" and you will find sites like below:
lexilogos.com/keyboard/russian.htm
http://russian.typeit.org/
http://www.apronus.com/internet/ruskey.htm
Then, you can use LaTeX to write Russian with babel help as described here:
https://tex.stackexchange.com/a/72690/120578:
MWE:
\documentclass{article}
\usepackage[T2A,T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage[russian,english]{babel}
\begin{document}
Text in English
\begin{otherlanguage*}{russian}
Текст на русском языке
\end{otherlanguage*}
A word and another \foreignlanguage{russian}{слово}
\end{document}
Or XeLaTeX (to have the ability of using many fonts) like described here:
https://tex.stackexchange.com/a/835/120578:
MWE:
\documentclass{article}
\usepackage{fontspec} % loaded by polyglossia, but included here for transparency
\usepackage{polyglossia}
\setmainlanguage{russian}
\setotherlanguage{english}
% XeLaTeX can use any font installed in your system fonts folder
% Linux Libertine in the next line can be replaced with any
% OpenType or TrueType font that supports the Cyrillic script.
\newfontfamily\russianfont[Script=Cyrillic]{Linux Libertine}
\begin{document}
Привет
\begin{english}
Hello!
\end{english}
\end{document}
More here: tex.stackexchange.com/questions/816/cyrillic-in-latex.
amsfonts, although i think most participants in this forum don't consider it mainstream. but if you're interested, i can provide more details tomorrow. – barbara beeton Oct 13 '17 at 00:36