I have a US keyboard and the accents are located different. Using accent characters in LibreOffice seems a bit more cumbersome than in MS Office…
US citizens will appreciate their being neighbours of Canadians, and in Canada there are many native French speakers.
Thus I would assume there is a simple way to get French special chacters using a US styled keyboard.
Then you altered something in your keyboard configuration/management because this should not occur.
OK, you want to use IPA fonts.
If you are a Windows user (if not, sorry), you may want to install SIL IPA fonts and Keyman Desktop.
https://software.sil.org/fonts/
(Choose ‘Latin, Greek, and Cyrillic Fonts’, Charis SIL, or Doulos SIL)
The method I use is to employ the ASCII codes with the keyboard in Numlock.
Hence à is ALT and 133, é is ALT and 130 etc. This works in e-mail clients such as Thunderbird and on web sites as well.
Lists of ASCII codes are readily available on the web.
(Welcome!)
The original question contained the (small) engma (U+014B) as an example, and talked of IPA extensions.
It thus was about characters not available using ASCII.
Do you know of a related update of the Alt+NumPad feature?
I was just looking at the topic heading and did not appreciate the particular problem detailed by the initial poster.