Problem with Cyrillic letters

Question

I used to write papers in English but now I have to type paper in Ukrainian. So I've got a couple of mistakes trying to make it.

Example

\documentclass[14pt,a4paper]{extarticle}
\usepackage[T2A]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage[ukrainian,english]{babel}

\begin{document}
В рівноважній статистичній механіці.
\end{document}

Error

! Package inputenc Error: Unicode char \u8:̆ not set up for use with LaTeX.

Of course, I've searched a lot at TeX SX and also tried

\usepackage[utf8x]{inputenc}

and got

! Package ucs Error: Please activate option 'combine'.

While trying to use \usepackage[combine]{ucs} option I get the following error

! LaTeX Error: Option clash for package ucs.
! Package ucs Error: Please activate option 'combine'.

Any ideas what's wrong? Interesting fact that when I type text directly in TeX editor, everything is OK, but if I paste text from pdf I have these errors. Of course, you can advice me to type all the text but it's hard to type hundreds of pages on my own.

Answer 1

pdflatex is not able to handle combining accents; you should directly use U+0439 rather than the combination U+0438 and U+0306.

\documentclass[14pt,a4paper]{extarticle}
\usepackage[T2A]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage[ukrainian]{babel}

\begin{document}
В рівноважній статистичній механіці.
\end{document}

Answer 2

Using babel with more than one language option as in your case you should be aware of the following (babel manual version3.9r from 2016/4/23)

In multilingual documents, just use several option. So, in LATEX2e the preamble of
the document:
\documentclass{article}
\usepackage[dutch,english]{babel}
would tell LATEX that the document would be written in two languages, Dutch and
English, and that English would be the first language in use, and the main one.

\usepackage[ukrainian,english]{babel} would use the English language not the Ukrainian. The one typed last i.e. english would be the one selected, if you do not add a \selectlanguage{ukrainian} to your code.