Breaking paragraph into lines with courier in cals table

Question

\documentclass[10pt,a4paper]{article}
\usepackage[utf8]{inputenc}
\usepackage[a4paper]{geometry}
\geometry{top=10mm, bottom=10mm, left=10mm, right=10mm}
\geometry{showframe}
\usepackage{courier}
\usepackage[T1]{fontenc}
\usepackage{cals}

\makeatletter

\begin{document}
%\renewcommand*\familydefault{\sfdefault}
\renewcommand*\familydefault{\ttdefault}
\normalfont

\begin{calstable}

\colwidths{
{15pt}
{10pt}
{515.60239pt}
}
\cals@paddingL=1pt
\cals@paddingR=1pt
\def\cals@borderT{0.2pt}
\def\cals@borderB{0.2pt}
\def\cals@borderL{0.2pt}
\def\cals@borderR{0.2pt}
\brow
\alignR \cell{\strut E}
\alignC \cell{\strut =}
\alignL \cell{\strut this is the english text, this is the english text, this is the english text, this is the english text, this is the english text, this is the english text, this is the english text}
\erow

\end{calstable}

Why doesn't the text break in the rigth place? In case of using sfdeault, it's good. 
\end{document}

Answer 1

This is similar to How to get long \texttt sections to break. By default the tt font does not have stretachable interword spaces and so there is not much room for TeX to manoevre when choosing line breaks. Adding some stretchability improves the line breaking:

\documentclass[10pt,a4paper]{article}
\usepackage[utf8]{inputenc}
\usepackage[a4paper]{geometry}
\geometry{top=10mm, bottom=10mm, left=10mm, right=10mm}
\geometry{showframe}
\usepackage{courier}
\usepackage[T1]{fontenc}
\usepackage{cals}
\makeatletter

\newcommand*\flextt{%
  \ttfamily
  \fontdimen2\font=0.4em% interword space
  \fontdimen3\font=0.2em% interword stretch
  \fontdimen4\font=0.1em% interword shrink
  \fontdimen7\font=0.1em% extra space
}

\begin{document}
\flextt

\begin{calstable}

\colwidths{
{15pt}
{10pt}
{515.60239pt}
}
\cals@paddingL=1pt
\cals@paddingR=1pt
\def\cals@borderT{0.2pt}
\def\cals@borderB{0.2pt}
\def\cals@borderL{0.2pt}
\def\cals@borderR{0.2pt}
\brow
\alignR \cell{\strut E}
\alignC \cell{\strut =}
\alignL \cell{\strut this is the english text, this is the english text, this is the english text, this is the english text, this is the english text, this is the english text, this is the english text}
\erow

\end{calstable}

Why doesn't the text break in the rigth place? In case of using sfdeault, it's good. 
\end{document}

Answer 2

It's always a big deal trying to break words in tt fonts.

You can try using a sloppypar environment:

\documentclass[10pt,a4paper]{article}
\usepackage[utf8]{inputenc}
\usepackage[a4paper]{geometry}
\geometry{top=10mm, bottom=10mm, left=10mm, right=10mm}
\geometry{showframe}
\usepackage{courier}
\usepackage[T1]{fontenc}
\usepackage{cals}

\makeatletter

\begin{document}
%\renewcommand*\familydefault{\sfdefault}
\renewcommand*\familydefault{\ttdefault}
\normalfont

\begin{calstable}

\colwidths{
{15pt}
{10pt}
{515.50239pt}
}
\cals@paddingL=1pt
\cals@paddingR=1pt
\def\cals@borderT{0.2pt}
\def\cals@borderB{0.2pt}
\def\cals@borderL{0.2pt}
\def\cals@borderR{0.2pt}
\brow
\alignR \cell{\strut E}
\alignC \cell{\strut =}
\alignL \cell{\begin{sloppypar}\strut this is the english text, this is the english text, 
this is the english text, this is the english text, this is the english text, 
this is the english text, this is the english text\end{sloppypar}}
\erow

\end{calstable}

Why doesn't the text break in the rigth place? In case of using sfdeault, it's good.
\end{document}

Output: