Oh, I've confirmed it (Comment #7).

Thank you!

I think I've found a different issue which is not related to the tipauni package.

I've played with the International Phonetical Alphabet Keyboard (2015 revised edition).

https://www.internationalphoneticalphabet.org/html-ipa-keyboard-v1/keyboard/

I've noticed that by inputting this,
I've got a result such that `n's are equally spaced regardless of whether a diacritics is attached or not.
file #489

But this code has brought non-equally spaced `n's.
\documentclass{article} \usepackage{fontspec} \setmainfont{CharisSIL} \pagestyle{empty} \begin{document} Raw UTF-8: nn̚nn̚nn \end{document}

What do you think?

Please, check this case:
\documentclass{article} \usepackage{tipauni} \begin{document} \typeout{Raw UTF-8} Raw UTF-8: n̚ \typeout{Input B} Input B: \textipa{n\tc} \typeout{Input A: PLEASE, CHECK THIS!!!} Input A: n\textcorner \end{document}

With the older definition, it brings an error:

By the way, have you confirmed that the correction is appropriate?

Because I'm not familar with the IPA symbols, it might happen that this modification is wrong.

In tipauni.dtx,

\textcorner should be defined by \DeclareTextSymbol instead of \DeclareUnicodeAccent,
since \textrhoticity is defined by \DeclareTextSymbol.