I switched to lualatex for coloring part of Arabic words easily with arabluatex and xcolor. With xelatex I'd no problem with Bangla.
Here's the latex script:
\documentclass[12pt]{report}
\usepackage{arabluatex, fontspec, xcolor}
\setmainfont{[Kalpurush]}
\newfontfamily\arabicfont[Script = Arabic]{Al Qalam Quran Majeed Web}
\newcommand{\textarabic}[1]{\bgroup\textdir TRT\arabicfont #1\egroup} % Arabic inside LTR
\newcommand{\n}[1]{\bgroup\textdir TLT #1\egroup} % for digits inside Arabic text
\newcommand{\afootnote}[1]{\footnote{\textarabic{#1}}} % Arabic footnotes
\newenvironment{Arabic}{\textdir TRT\pardir TRT\arabicfont}{} % Arabic paragraph
\def\r{\color{red}}
\setlength\parindent{0pt}
\begin{document}
কণ্যা এখন কি করিবে? \\
\textarabic{وَ{\r لَ}دٌ}\\
\textarabic{{\r ٱل}كَلَمُ}\\
\textarabic{أَبَ{\r كُم}}
\end{document}
and here's the output:
Bangla output in the first line should have been: কণ্যা এখন কি করিবে?
How to fix Bangla in lualatex?


Traditional Arabicdoesn't work at all, withSimplified Arabicit works to some extent but alphabets actually get disunified, withArabic Typesettingit doesn't work well! I foundAl Qalam Quran Majeed Webin an article and so far it's working nicely. – May 28 '19 at 15:43xelatexArabic broke apart, I'd tried this code. – May 28 '19 at 19:05pdftoxeorluainsettingsto make it work for me and it did perfectly, butharfisn't working in VS Code! I'veMikTex 2.9installed in my System. – May 28 '19 at 20:41harftexseems very complicated! – May 28 '19 at 21:16