Fulio said:
I wanted to present the letters 'r' and 'z' with a dot under them.
Please open the following page to see what they look like. I hope I
can do it with the unicode.
http://www.pinyinology.com/listing/ipa_letters.html
The image indeed seems to contain 'r' and 'z' with a dot under, but this is
odd, if the notation is supposed to be IPA. As currently defined, IPA does
not use dot under.
Although the Unicode standard refers to the use of dot under as IPA usage,
this actually refers to obsolete versions of IPA. Moreover, the old IPA
usage is, as the Unicode standard says, to indicate "closer variety of
vowel". On the other hand, the standard also says: "Americanist and
Indo-Europeanist: retraction or retroflexion".
It is thus unclear what the notation is supposed to mean and what the
notational system is, but anyway it isn't modern IPA. If you are about to
represent some old text in HTML format, then you might decide to use the
same characters as the old text uses, even if it is outdated notation. In
that case, the advice given by others is sufficient (though you could also
write the characters as such, using the tools of the editor you're using -
there should be no necessity of using character references for them when
your encoding is UTF-8, as it is). But this really depends on your goals.
My guess is that in your text, r with dot below is supposed to denote a
syllabic (post)alveolar approximant, roughly the same as the sound between
"p" and "t" in Standard American pronunciation of the word "particular". In
IPA, the symbol for it is U+0279 U+0329, i.e. LATIN SMALL LETTER TURNED R
followed by COMBINING VERTICAL LINE BELOW. (There is no single code point
representation for this, i.e. it does not exist as a precomposed character.)
Thus, it could be written in HTML as
ɹ̩
I have no idea of what z with dot below might refer to here.