Please consider the following MWE:
\documentclass{article}
\usepackage[spanish]{babel}
\selectlanguage{spanish}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\begin{document}
Works: áéà
Does not work: \(\pmod1\)
\end{document}
The áéà text is copied correctly, but if I try to copy (mód 1) it says: (m´od 1).
Does anyone know why this happens? How is it solved?
Thanks!

listingspackage. Any idea how to fix it? – manooooh Aug 28 '18 at 03:26\usepackage[spanish, english]{babel} \selectlanguage{spanish}. – Zarko Aug 28 '18 at 03:34englishoption but now it does not have accent, i.e. it displays as(mod 1)and copy as(mod 1):(((. – manooooh Aug 28 '18 at 03:40enumerateoptions (using my code) and the third level or something like that the enumeration format isI), II), ...(I would have liked them to appear in lowercase, but nvm). Anyway, when I add that option all the enumeration goes crazy and, for that example, the actual enumeration isi), ii), .... Weeeeird. – manooooh Aug 28 '18 at 03:54pdflatex(all packages updated yesterday) and got good copy text with SumatraPDF, but Adobe Reader gave me(mod 1), Firefox, Chrome and Edge all said(m ́od 1). (Of course this still shows that something is off, the consensus between viewers here is the wrong paste text, which is not good.) – moewe Aug 28 '18 at 04:23spanish.ldfis the file read bybabelthat provides support for the Spanish language. This redefines\pmodto dom\es@op@ac odand\es@op@ac obasically does\acute{o}, which will not use a precomposed character, whence the issue you have. – egreg Aug 28 '18 at 08:47