\documentclass[10pt,a4paper]{article}
\font\olsleight=olsl8 scaled 1000
\font\olslnine=olsl9 scaled 1000
\font\olslten=olsl10 scaled 1000
\font\olsltwelve=olsl12 scaled 1000
\font\olsltt=olsltt10 scaled 1000
\newcommand{\Ligature}{%
\input test_alphabet.tex
}
\begin{document}

Computer Modern Roman:\\{\Ligature}

Slanted Roman 8pt:\\{\olsleight \Ligature}

Slanted Roman 9pt:\\{\olslnine \Ligature}

Slanted Roman10pt:\\{\olslten \Ligature}

Slanted Roman 12pt:\\{\olsltwelve \Ligature}

Slanted Typewriter Text 10pt:\\{\olsltt \Ligature}

\end{document}