TeX Live 2018 is great with default UTF-8 encoding. Unicode characters display correctly "as is" now, by default.

What should I minimally install for other languages (Chinese, Vietnamese, scientific unicode symbols, etc)?

Accepted Answer

Although no MWE was included, the answer indeed does put multiple languages as well as math/science symbols in a single LaTeX document.

Trying out XeLaTeX

This code doesn't work.

documentclass{book}



usepackage{fontspec}



% usepackage{xeCJK}

% setCJKmainfont{SimSun}



begin{document}



Testing UTF-8 character here: é



Vietnamese: Tiếng Việt



And English again.



%Chinese: 中文



Temperature: 26°C



Math symbols: $ℝ$



end{document}

Issues to fix: Unicode math symbol, package for SimSun font.

To use Chinese in your document: Read here. In short: use CJKutf8.

To use Vietnamese in a LaTeX document, I often use usepackage[vietnamese]{babel} or usepackage[utf8]{vietnam} (the latter way is not recommended).

To use math symbols, do as usual. LaTeX is intelligent enough so that you don't have to go to some source to copy and paste the letter, for example, ℝ. For the letter ℝ, you can use $mathbb{R}$ from amssymb package. For a sufficient list of such symbol, you can read this document.¹

The same happens for the degree symbol. I would do $26^circ$, which is much easier than 26°C. I'm sure there are some even simpler ways to typeset "26 degrees Celcius".

To enter some special Unicode letters, read here. There are some answers in that question which use pdf(La)TeX.

Edit 1

About "human readability"

I have seen many (La)TeX users complaining about the readability in LaTeX. You know, LaTeX is rather a "programming language" than a what-you-see-is-what-you-get software.

Here is some ways to solve the issue:

1. Use LyX: LyX is a WYSIWYG software for LaTeX users. I don't use LyX, so I don't know much about it (I'm sorry). You can search on Wikipedia, etc.



2. 
   

   Use macros: Let me take an example. You see that if you type $26^circ$, it is not so read-able, don't you? In that case, I suggest define your own command which you can see it clearly:

   
   
   

   newcommand{degreecelcius}{$^circtext{C}$} % Add this to your preamble
   
   

   
   
   

   Now, see what you have:

   
   
   

   documentclass{article}
   
   usepackage{amsmath}
   
   newcommand{degreecelcius}{$^circtext{C}$}
   
   begin{document}
   
   The temperature in Vietnam last night was about 22degreecelcius.
   
   end{document}
   
   

   
   
   

   

   
   

Besides, I have known some more ways to type "degree Celcius". For example:

documentclass{article}

usepackage{textcomp}

begin{document}

The temperature in Vietnam last night was about 22textdegree C.

end{document}

It is easy to read, right?

Fun TeXing!

¹ One of the authors of the document is our TeXpert David Carlisle (#2 overall). Thank you very much, Mr. Carlisle.

You can use a combination of unicode-math and babel for this, in XeTeX or LuaLaTeX. Substitute any TrueType or OpenType fonts of your choice into this template:

documentclass[varwidth = 10cm, preview]{standalone}

% For demonstration purposes only.  Change to book, or whatever document

% class you need



usepackage{unicode-math}

usepackage[english]{babel}

usepackage{microtype}



babelprovide{vietnamese}

% Due to a bug in Babel 3.22, the package does not pass the correct script

% option to fontspec, and we must patch it with this workaround:

babelprovide[script = CJK,

              language={Chinese Simplified}]{chinese-simplified}



babelfont{rm}[Scale = 1.0]{Noto Serif}

defaultfontfeatures{ Scale = MatchUppercase }

babelfont{sf}{Noto Sans}

babelfont[chinese-simplified]{rm}[Ligatures = {Common, Discretionary}]{Noto Serif CJK SC}

babelfont[chinese-simplified]{sf}[Ligatures = {Common, Discretionary}]{Noto Sans CJK SC}

setmathfont{STIX Two Math}



begin{document}



Testing UTF-8 character here: é



Vietnamese: foreignlanguage{vietnamese}{Tiếng Việt}



And English again.



Chinese: foreignlanguage{chinese-simplified}{中文}



Temperature: 26°C % Or 26textcelsius



Math symbols: $ℝ$ % Or $mathbb{R}$



end{document}

If you don’t have these fonts installed, they area available on CTAN as notoCJKsc, or from the GitHub repo.

Unfortunately, there are many other bugs with the language definitions in Babel. Two that I’ve noticed are with Japanese (which requires a similar workaround to Chinese with script = Kana) and Hebrew, which has no such easy fix. It works in polyglossia, but unfortunately, polyglossia supports fewer languages than babel.