This is pdfTeX, Version 3.14159265-2.6-1.40.18 (TeX Live 2017) (preloaded format=mex 2018.10.6)  25 JUL 2019 12:54
entering extended mode
 restricted \write18 enabled.
 %&-line parsing enabled.
**c
(/usr/local/texlive/2017/texmf-dist/tex/mex/base/mex.tex
This is MeX  Version 1.05  18 XII 1993  (B. Jackowski & M. Ry\'cko)
Preloading the MeX format:
(/usr/local/texlive/2017/texmf-dist/tex/mex/base/mex1.tex
polish auxiliary macros,
Runaway definition?
#1#2#3#4#5->\expandafter \def \csname f@nt#1\endcsname {#3}\donothyph@nate \ETC
.
! Forbidden control sequence found while scanning definition of \d@finelanguage
.
<inserted text> 
                }
<to be read again> 
                   \newlanguage 
l.350     \e\toks\e1\e{\e\newlanguage
                                     \csname#1language\endcsname}%
? 
! Emergency stop.
<inserted text> 
                }
<to be read again> 
                   \newlanguage 
l.350     \e\toks\e1\e{\e\newlanguage
                                     \csname#1language\endcsname}%
End of file on the terminal!

No pages of output.
