If I try to copy and paste text from Wikipedia with Greek letters into my LaTeX files in the resulting PDF files only about 70% of the Greek letters are visible. I am using XeLaTeX. E.g., If I have the following TeX file:
\documentclass[proc,german,a4g,a4paper]{article}
\usepackage{unixode}
\begin{document}
{\bf Physik} : Naturlehre: aus griechisch $φυσική$
$
\begin{array}[h]{ccllll}
\hline
\multicolumn{2}{c}{Buchstabe}&\multicolumn{2}{c}{Name}&\multicolumn{2}{c}{Aussprache}\\
\multicolumn{2}{c}{}&\multicolumn{2}{c}{}&Altgr.&Neugr.\\
\hline
Α & α & alpha & άλφα & [a] [aː] & [a] \\
Β & β & beta & βήτα & [b] & [v] \\
Γ & γ & gamma & γάμμα & [ɡ] & [ɣ] ~ [ʝ] \\
Δ & δ & delta & δέλτα & [d] & [ð] \\
Ε & ε & epsilon & έψιλον & [e] & [e] \\
Ζ & ζ & zeta & ζήτα & [zd] & [z] \\
Η & η & eta & ήτα & [ɛː] & [i] \\
Θ & θ & theta & θήτα & [tʰ] & [θ] \\
Ι & ι & iota & ιώτα & [i] [iː] & [i] \\
Κ & κ & kappa & κάππα & [k] & [k] ~ [c] \\
Λ & λ & lambda & λάμδα & [l] & [l] \\
Μ & μ & mu & μυ & [m] & [m] \\
Ν & ν & nu & νυ & [n] & [n] \\
Ξ & ξ & xi & ξι & [ks] & [ks] \\
Ο & ο & omicron & όμικρον & [o] & [o] \\
Π & π & pi & πι & [p] & [p] \\
Ρ & ρ & rho & ρώ & [r] & [r] \\
Σ & σ/ς & sigma & σίγμα & [s] & [s] \\
Τ & τ & tau & ταυ & [t] & [t] \\
Υ & υ & upsilon & ύψιλον & [y] [yː] & [i] \\
Φ & φ & phi & φι & [pʰ] & [f] \\
Χ & χ & chi & χι & [kʰ] & [x] ~ [ç] \\
Ψ & ψ & psi & ψι & [ps] & [ps] \\
Ω & ω & omega & ωμέγα & [ɔː] & [o] \\
\hline
\end{array}
$
\end{document}
In the created pdf file the capital letters are only shown for gamma, delta, theta, lambda, xi, pi, sigma, phi, psi and omega. Fromt the six letters of the word φυσική in the header only four letters φσικ are shown in the pdf. Emacs shows me for the small nu in φυσική the UNICODE #x3c3 and for the small nu in the alphabet #x3bd. The ɡ in the first sound column for gamma has the UNICODE #x5d and is not shown, while the g in the first name column has the UNICODE #x61 and is shown.
Xelatex reports about versions:
rose@impala:/home/rose/Txt/lectures/TeX_Test(84)$ xelatex -v
XeTeX 3.14159265-2.6-0.99992 (TeX Live 2015)
kpathsea version 6.2.1
Copyright 2015 SIL International, Jonathan Kew and Khaled Hosny.
There is NO warranty. Redistribution of this software is
covered by the terms of both the XeTeX copyright and
the Lesser GNU General Public License.
For more information about these matters, see the file
named COPYING and the XeTeX source.
Primary author of XeTeX: Jonathan Kew.
Compiled with ICU version 55.1; using 55.1
Compiled with zlib version 1.2.8; using 1.2.8
Compiled with FreeType2 version 2.6.2; using 2.6.2
Compiled with Graphite2 version 1.2.4; using 1.2.4
Compiled with HarfBuzz version 1.1.2; using 1.1.2
Compiled with libpng version 1.6.20+apng; using 1.6.20+apng
Compiled with poppler version 0.39.0
Compiled with fontconfig version 2.11.94; using 2.11.94
rose@impala:/home/rose/Txt/lectures/TeX_Test(85)$
Best Answer
It is only a matter of choosing the correct font, so it seems to me. I used Linux Libertine O as the main font and everything looks fine:
But I have those fonts installed. Another way to use these fonts is as a package with
\usepackage{libertine}. Then, you will not need the\setmainfontoption.